Ben Cowling @bencowling88 Twitter profile

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Ben Cowling

@bencowling88

4 years

(1/2) New study just out, face masks effective for source control against influenza and seasonal coronaviruses, even reducing virus detection in aerosols in patients with coronavirus infections. 5 years of hard work to generate the data

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Ben Cowling

@bencowling88

2 years

While it looks like Macau have got the current outbreak under control, after 13 rounds of universal testing, weeks of mobility restrictions, and more than a week of total lockdown, this was the first time in two years that such stringent measures have ...

Opinion | Macau’s costly two-week Covid-19 lockdown holds lessons for Hong Kong

It has taken Macau numerous rounds of mass testing and weeks of lockdown to bring the latest outbreak under control. In Hong Kong, we have to wonder if we can continue to afford stringent pandemic...

www.scmp.com

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Ben Cowling

@bencowling88

4 years

Why Telling People They Don’t Need Masks Backfired

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Ben Cowling

@bencowling88

3 years

@DrEliDavid @FatEmperor @Mangan150 @zoeharcombe @JoannaBlythman @Francis_Hoar @ProfTimNoakes @justin_hart @kerpen @prof_freedom @LukeJohnsonRCP Nonsense to say that masks can't block aerosols, we used exactly the same device to show that masks can block aerosols in this publication, we just have to recognise that they won't be 100% effective

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Ben Cowling

@bencowling88

4 years

(1/7) Worrying indications that the second wave of COVID-19 has now begun in Hong Kong, with more than 50 local infections being identified in the past few days and a large number expected to be reported later today.

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Ben Cowling

@bencowling88

3 years

Influenza disappeared from most of the world in the past 18 months, when influenza transmission was suppressed by the anti-COVID public health measures. But now influenza B is spreading again in mainland China and detections are increasing each week (1/9)

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Ben Cowling

@bencowling88

4 years

They’ve Contained the Coronavirus. Here’s How.

Opinion | They’ve Contained the Coronavirus. Here’s How. (Published 2020)

Singapore, Taiwan and Hong Kong have brought outbreaks under control — and without resorting to China’s draconian measures.

www.nytimes.com

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Ben Cowling

@bencowling88

1 year

New preprint on Omicron severity just out. Key findings – intrinsic severity of Omicron is similar to ancestral Wuhan strain, but effective (observed) severity of Omicron is reduced in people who have been vaccinated and/or previously infected (1/16)

Intrinsic and effective severity of COVID-19 cases infected with the ancestral strain and Omicron...

Background Understanding severity of infections with SARS-CoV-2 and its variants is crucial to inform public health measures. Here we used COVID-19 patient data from Hong Kong to characterise the...

www.medrxiv.org

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Ben Cowling

@bencowling88

3 years

Latest news from Hong Kong (zero cases for 5 months now) - masks are mandatory in schools, and children are being asked to purchase special masks in order to attend instrument lessons . I thought it was a joke when I saw the picture. It's not a joke. Cost US$23, reusable.

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Ben Cowling

@bencowling88

2 years

(1/34) I saw this recent article in the BMJ, and I want to write a thread to explain (1) masks likely have a small to moderate effect on transmission, and (2) I don't believe the estimated 53% reduction here is a valid estimate of the mask effect

Effectiveness of public health measures in reducing the incidence of covid-19, SARS-CoV-2 transmi...

Objective To review the evidence on the effectiveness of public health measures in reducing the incidence of covid-19, SARS-CoV-2 transmission, and covid-19 mortality. Design Systematic review and...

www.bmj.com

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Ben Cowling

@bencowling88

4 years

(2/2) Collaborative project with @Don_Milton using the G2 machine that he designed. One of the co-authors with her head in the machine shown here:

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Ben Cowling

@bencowling88

2 years

We're able to report our estimates of the effectiveness of COVID-19 vaccines, led by @martinamc_m with @joshnealon @gmleunghku Both BNT and Sinovac vaccines provide good protection against severe Omicron BA.2; but elderly who received 2xSinovac need a 3rd dose of vaccine (1/15)

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Ben Cowling

@bencowling88

2 years

In quarantine hotel in Hong Kong, just reading the quarantine hotel FAQs. #20 is a disaster waiting to happen

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Ben Cowling

@bencowling88

4 years

(1/10) Just posted our new preprint on the successful suppression of first wave of #COVID19 in Hong Kong with @gmleunghku

Suppressing COVID-19 transmission in Hong Kong: an observational study of the first four months

Background: Hong Kong was one of the first locations outside of mainland China to identify COVID-19 cases in January 2020. We assessed the impact of various public health measures on transmission.M...

www.researchsquare.com

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Ben Cowling

@bencowling88

2 years

This is fascinating because on-arrival quarantine is still set at 21 days, and the unnecessary 3rd week actually seems to have caused this particular community outbreak

Aaron Busch

@tripperhead

2 years

CHP Controller Edwin Tsui: We know the incubation period for Omicron is around 3 days. This is why we are doing 5 day lockdowns.

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Ben Cowling

@bencowling88

3 years

Having been in the UK for a few weeks, I'm at Heathrow about to board BA31 back home to Hong Kong. I'll start a thread to document my experiences (1/x)

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Ben Cowling

@bencowling88

3 years

Short thread on #COVID19 vaccines and vaccine hesitancy in Hong Kong. tl;dr summary: vaccines work, we should all choose to get vaccinated so that Hong Kong can get back to normal (1/17)

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Ben Cowling

@bencowling88

4 years

(1/9) Good news about COVID-19 suppression in Hong Kong, today we estimate that the daily reproductive number Rt dropped below 1 on 22 July, around a week ago

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Ben Cowling

@bencowling88

2 years

Hotel quarantine can *delay* the introduction of new strains into our community but it will not ultimately prevent their introduction. The 7-day quarantine policy has enormous economic costs to our city and very limited benefit.

Aaron Busch

@tripperhead

2 years

⚠️🇭🇰🦠 BA.2.12.1 cases found in community. Suspected DQH transmission Two travellers tested positive via Day 12 test at CTC. Two other cases found in same hotel at same time of stay. 11 places (including restaurants) visited by the couple post DQH will be on CTN.

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Ben Cowling

@bencowling88

3 years

Our team have just collaborated with Guangdong CDC on a new preprint (not yet peer-reviewed) on the COVID outbreak in Guangzhou in May-June, and in this thread I’m going describe one of the findings relevant to quarantine durations (1/16)

Transmission dynamics and epidemiological characteristics of Delta variant infections in China

Background The Delta variant of SARS-CoV-2 has become predominant globally. We evaluated the transmission dynamics and epidemiological characteristics of the Delta variant in an outbreak in southern...

www.medrxiv.org

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Ben Cowling

@bencowling88

4 years

(10/10) In combination, traveler quarantine, test+trace, face masks, and moderate physical distancing, all contributed to the successful suppression of #COVID19 in Hong Kong without needing to resort to a lockdown.

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Ben Cowling

@bencowling88

3 years

I know of no scientific evidence to justify a 21-day quarantine period. 10 days with an exit test should be enough, 14 days more than enough. Anyone whose suspected exposure in Dorsett WC was only in the third week after their arrival was needlessly put at risk of infection...

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Ben Cowling

@bencowling88

2 years

@cqmrns_tg Every week we seem to discover another downside to our ZeroCovid strategy, while one of the major advantages (quarantine-free travel with mainland) still hasn't materialised I am very sad about the hamsters

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Ben Cowling

@bencowling88

4 years

Here is an update on the #COVID19 situation in Hong Kong, following from my thread last week (1/18)

Real-time dashboard

covid19.sph.hku.hk

Ben Cowling

@bencowling88

4 years

(1/9) Good news about COVID-19 suppression in Hong Kong, today we estimate that the daily reproductive number Rt dropped below 1 on 22 July, around a week ago

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Ben Cowling

@bencowling88

2 years

I would like to know what scientific evidence is being used to justify the continued requirement that COVID vaccination uptake /must reach a specified level/ before it's safe for primary schools and secondary schools to operate for full days. I am not aware of such evidence.

RTHK English News

@rthk_enews

2 years

The #HongKong government has announced the easing of #COVID19 jab requirements for both secondary and primary students relating to full-day classes

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Ben Cowling

@bencowling88

4 years

(1/16) However, I don't follow the argument that the guidance has changed because of new evidence. The evidence has been there all along. I have a few comments on the most recent review in the Lancet

Ben Cowling

@bencowling88

4 years

This is really great news! Masks can make a difference and should be recommended. Providing additional materials on when and how to wear masks is also very helpful.

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Ben Cowling

@bencowling88

2 years

@DrDOwens Outdoor masking has minimal benefit, I agree with @DrDOwens that it adversely affects the credibility of health officials I would recommend rescinding the outdoor mask mandate as soon as possible Requiring masks to be worn during sporting activities will do more harm than good

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Ben Cowling

@bencowling88

2 years

Increasing the stringency of home isolation for cases in Hong Kong, with electronic tracking bracelets, will have a minimal effect on transmission. Scientific basis for my assessment is in the thread which follows … (1/27)

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Ben Cowling

@bencowling88

4 years

Would everyone wearing face masks help us slow the pandemic?

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Ben Cowling

@bencowling88

3 years

@DrEliDavid @FatEmperor @Mangan150 @zoeharcombe @JoannaBlythman @Francis_Hoar @ProfTimNoakes @justin_hart @kerpen @prof_freedom @LukeJohnsonRCP Don't let perfect be the enemy of good. Masks can reduce transmission, but it's unreasonable to expect them to completely stop transmission

Face masks and COVID-19: don’t let perfect be the enemy of good

www.eurosurveillance.org

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Ben Cowling

@bencowling88

3 years

Fantastic to see Singapore following the science on quarantine duration

COVID quarantine period to be cut from 14 days to 10 days: Ong Ye Kung

The period for individuals under COVID-19 quarantine will be reduced from 14 days to 10 days as the Delta variant has a shorter incubation period, the multi-ministry taskforce said.

sg.news.yahoo.com

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Ben Cowling

@bencowling88

1 year

Landed in Hong Kong for the third time in a month, the first two times no queue, third time today there’s a 15 minute queue for the PCR test!

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Ben Cowling

@bencowling88

3 years

I was interviewed on CNBC this morning, explaining that #zerocovid is not a sustainable strategy in the long term

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Ben Cowling

@bencowling88

4 years

(7/7) When the second epidemic is controlled, this really emphasises the importance of keeping infections out through effective testing and quarantine of persons arriving in Hong Kong. Once an epidemic begins, it will take a lot of effort to stop.

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Ben Cowling

@bencowling88

4 years

(3/7) Clusters have been identified in an elderly home, a public housing estate, and linked with some restaurants. Test+trace has not prevented this. Mask-wearing in public is still universal, and has not prevented this.

Officials warn of hospital care crunch as Hong Kong hit with 38 new Covid-19 cases

Fresh cluster discovered at public housing estate, adding to existing ones centred around elderly care home, restaurants and taxi drivers Students will begin summer holidays early, but health...

www.scmp.com

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Ben Cowling

@bencowling88

4 years

(1/2) Fascinating article just out in Nat Microbiol. SARS-CoV-2 could be detected in samples collected in the ILI sentinel surveillance network in Wuhan from the first week of January 2020 onwards

SARS-CoV-2 detection in patients with influenza-like illness

Nature Microbiology - Here, it is shown that there was community transmission of SARS-CoV-2 early in January.

www.nature.com

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Ben Cowling

@bencowling88

2 years

@hkfp @tomgrundy You might be able to re-use this headline almost every day for the next month …

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Ben Cowling

@bencowling88

1 year

@YanzhongHuang “lying flat” is the new “not lying flat”

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Ben Cowling

@bencowling88

2 years

If the epidemic situation is considered "severe", what is the marginal benefit of a hamster cull? There are still no documented hamster-to-human infections, and there could be better uses of resources for epidemic control? Just put a CTN on ppl who recently purchased hamsters ...

RTHK English News

@rthk_enews

2 years

Health officials warn that new #COVID19 cases in #HongKong have amounted to a "severe epidemic situation"

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Ben Cowling

@bencowling88

2 years

@tripperhead @CclLEUNG Vaccine pass should also be axed, alone with LeaveHomeSafe

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Ben Cowling

@bencowling88

3 years

Got my second dose of BioNTech earlier today, thanks to the great staff at Ap Lei Chau #HKTwitterGetsVaxxed

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Ben Cowling

@bencowling88

2 years

Maybe a silly question, but would these new measures have prevented any cases in the Moon Palace outbreak, if the measures had been in place for the last two weeks?

Aaron Busch

@tripperhead

2 years

Starting January 7th, all major events will need to cancel. Catering premises: After 6pm, no dine-in services. 6pm-4.59am. Maximum head count. 2 per table Cat B, 4 per table Cat C, 6 per table Cat D restaurants. KTV, mahjong etc closed. Bars/clubs closed.

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Ben Cowling

@bencowling88

2 years

Since 7 days quarantine is long enough based on the incubation period, why does it have to be 14 or 21 days for everyone else?

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Ben Cowling

@bencowling88

2 years

Wow, still sending mild cases to hospital?!

Aaron Busch

@tripperhead

2 years

Q: What happens with imported cases - still sent to hospital if confirmed? Any moves to reduce inbound quarantine to 7 days? Dr Au: They still get sent to hospital. And no.

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Ben Cowling

@bencowling88

4 years

Just Stop the Superspreading!

Opinion | Just Stop the Superspreading (Published 2020)

In our study, 20 percent of Covid-19 cases accounted for 80 percent of transmissions.

www.nytimes.com

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Ben Cowling

@bencowling88

2 years

Fascinating that new subvariants haven't replaced BA.2 in Hong Kong

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Ben Cowling

@bencowling88

2 years

Hong Kong reduced on-arrival quarantine to 7 days starting April 1st, and there’s one post-quarantine test on Day 12 I suspect it won’t be too long before a positive is found on a Day 12 test, but *not* because of a long incubation period …

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Ben Cowling

@bencowling88

2 years

@tripperhead @hkairport Just over 2 hours for me Process now much faster with RAT I continue to recommend relaxation of all travel-related measures, since we know the current measures aren’t watertight and won’t be able to keep new variants out of HK. Enormous economic costs, minimal benefit.

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Ben Cowling

@bencowling88

2 years

I support daily RAT testing but not if the parents are expected to pay for it Surely the govt should be paying for the tests for all children?! I’m disappointed to see coercion of COVID vaccination in children, I think it’s inappropriate

Aaron Busch

@tripperhead

2 years

Under Secretary for Education Dr Choi Yuk-lin: • daily rapid testing shouldn't be too much of a burden for most families • hopes schools can distribute RATs to families in need • if fit enough to want to do ECAs, fit enough to get vaccinated

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Ben Cowling

@bencowling88

2 years

Regarding Hong Kong quarantine policy, unless writing the previous policy as "7+7", don't call the new policy "3+4"? It's not a change from 7 to 3+4, it's a change from 7+7 to 3+4, with the addition of amber code in the medical surveillance period. Hopefully next step 0+0!

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Ben Cowling

@bencowling88

2 years

A lockdown now for 2 weeks would save many more lives than a lockdown in late March that is implemented to facilitate contact tracing during mass testing cycles. More stringent social distancing now, for two weeks, would slow down transmission as we approach the peak, ... (1/3)

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Ben Cowling

@bencowling88

2 years

Would be much more sensible to first reduce close contact quarantine to 10 days, doubling the effective capacity immediately When was the last time a case was picked up in penny’s bay after the 10th day of quarantine?

Aaron Busch

@tripperhead

2 years

Dr Chuang stated that the concept of home quarantine for close contacts is the absolute last possible option. Govt will attempt to find other quarantine centres.

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@bencowling88

2 years

Sounds like case 12382 must have been infected in their third week of quarantine, because 12374 only arrived on the 4th November? Is this yet another example of the third week of quarantine doing more harm than good?

Aaron Busch

@tripperhead

2 years

Professor YKY is now talking about the air draft from corridor towards rooms 1515 and 1517 possibly causing the cross-infection.

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@bencowling88

2 years

If there were a dangerous new variant somewhere in the world and HK wanted to /delay/ it’s spread in the Hong Kong community, flight suspensions with 3+ new-variant cases might make sense, but all the cases coming in are Omicron, of which we’ve got 1000+ infections per day …

Aaron Busch

@tripperhead

2 years

Q (BBG): Almost 60 flight bans this year. Shortage of DQH rooms. Biz community not happy. Any plans to remedy this? CL: Flight route suspension mechanism is staying. We're finding more rooms though.

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Ben Cowling

@bencowling88

3 years

New paper with @weywenlim and @sarahcobey - could fractionation solve the global shortage of #COVID19 vaccines? tl;dr we could consider reducing the dose of individual vaccines so that more people could receive at least some protection, more quickly (1/20)

Fractionation of COVID-19 vaccine doses could extend limited supplies and reduce mortality

Nature Medicine - Fractionation of COVID-19 vaccine doses could extend limited supplies and reduce mortality

www.nature.com

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Ben Cowling

@bencowling88

3 years

"Forget herd immunity, better to prepare to live with Covid-19: experts" (quoting me and @kkokwok ) via @scmpnews

Forget herd immunity, better to prepare to live with Covid-19: experts

Fast-spreading variants that render vaccines less effective have changed the game, say experts

www.scmp.com

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Ben Cowling

@bencowling88

3 years

We are going to pause the daily updates of Rt on our HKU COVID dashboard now that there are no recent local cases, and fingers crossed it will stay that way for a while!

Aaron Busch

@tripperhead

3 years

Real-time effective reproductive number of local COVID-19 cases: 0.6003📉

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Ben Cowling

@bencowling88

2 years

(1/10) Recent situation in hospitals in HK is very concerning. Following tweet includes information complied from daily press releases each of which refer to the preceding 24h (I excluded info on the approx 2000 mild cases isolated in Penny's Bay) ...

David Owens

@DrDOwens

2 years

Omicron is a greater threat to health systems than to individuals Health systems in ROW almost crashed by illness/isolation in HCW’s If health systems crash all cause mortality at all ages increases. People die of covid/heart disease/ asthma etc 1/5

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Ben Cowling

@bencowling88

2 years

I recommend children to get COVID-19 vaccination, but I don't think there's sufficient justification to *require* children to get vaccinated, and I'll explain my reasoning ... (1/15)

RTHK English News

@rthk_enews

2 years

The #HongKong government has announced that schools are required to have all of their staff members and at least 90 percent of students double-jabbed against #COVID19 in order to resume full-day in-person classes

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@bencowling88

2 years

For COVID-19, contact tracing works by identifying people who have been exposed to known cases typically based on prolonged close contact. It looks like contact tracing won't work as well against Omicron in HK -- transmission appears to be occurring without close contact? 1/4

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Ben Cowling

@bencowling88

3 years

Well done @nancyleung_hk for publishing this very comprehensive review of the transmission of respiratory viruses

Transmissibility and transmission of respiratory viruses

Nature Reviews Microbiology - In this Review, Leung provides an overview of the transmissibility and modes of transmission of respiratory viruses, the viral, host and environmental determinants of...

www.nature.com

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@bencowling88

2 years

@egyptiankinghk @xennialmatt @tripperhead Getting back to zero daily cases within the next few weeks is impossible It might not be impossible to get back to zero daily cases in perhaps 4 months from now, when potentially most of the population will be immune

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@bencowling88

1 year

Brief thread on containment vs mitigation. Summary point - I hope there's a plan for intense mitigation measures in China in the next 1-2 months, as part of the transition to living-with-COVID (1/9)

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Ben Cowling

@bencowling88

2 years

(34/34) Due to the flaws in the underlying studies, I don’t believe that the 53% risk reduction is a valid estimate of the real-world effectiveness of face masks. There’s good evidence that they work, I’m just not convinced by this specific estimate of their effectiveness

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Ben Cowling

@bencowling88

4 years

(2/7) Our estimate of the effective reproductive number "Rt" for local infections is close to 3, which is concerning It will take a lot of effort to bring down such a high reproductive number.

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Ben Cowling

@bencowling88

2 years

Hong Kong taxpayers are paying tens or even hundreds of millions of HK$ per month so we can tell other countries what strains are prevalent in their countries, and have a weeks advanced notice of what’s likely to be spreading in HK (which we can guess anyway)

Aaron Busch

@tripperhead

2 years

BA.5: 89.3% BA.4: 4.9% BA.2.12.1: 1.3% 29 XBB cases found in imported cases, 24 positive on arrival, five found on Day 2 testing. 44.8% came from Singapore

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Ben Cowling

@bencowling88

4 years

(5/7) Implementing work-from-home for civil servants and private businesses, closing bars and leisure facilities, and enhancing social distancing in restaurants was able to bring the first wave under control, and hopefully similar measures will be able to halt this second wave.

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Ben Cowling

@bencowling88

2 years

Hong Kong update - exponential rise in BA.4 and/or BA.5 (probably BA.5) continues. BA.2 cases now stable and will probably be declining soon, looks like we've hit herd immunity to this subvariant for now ... (1/6)

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Ben Cowling

@bencowling88

3 years

When I think about the public health rationale for the ZeroCovid strategy in the era of effective vaccines and effective treatments, I do sometimes wonder whether the same rationale would also support a ZeroInfluenza strategy and oppose "living with influenza"? (9/9)

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Ben Cowling

@bencowling88

2 years

@JShijiu @tripperhead ZeroCovid was a good strategy prior to the availability of vaccines, but has limited rationale after vaccines are widely available, and in my opinion it increases hesitancy in elderly (they may think the govt will protect them from getting COVID)

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Ben Cowling

@bencowling88

4 years

(6/7) How did the second wave start? We may never know, but given the absence of local cases for most of the past 3 months, these latest outbreaks may have been started by relatively more recent importations.

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Ben Cowling

@bencowling88

3 years

I got my first dose of BioNTech this morning at the Ap Lei Chau centre, very smooth process

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Ben Cowling

@bencowling88

3 years

Thread. Preliminary analysis of immune responses following receipt of BNT/Fosun and Sinovac vaccines with @weywenlim and @gmleunghku now published in Lancet Microbe. tl;dr we find substantial differences in antibody levels between the two vaccines (1/16)

Comparative immunogenicity of mRNA and inactivated vaccines against COVID-19

We report here comparative data on SARS-CoV-2 vaccine immunogenicity in health-care workers in Hong Kong who received either the BNT162b2 vaccine (Comirnaty; Fosun–BioNTech) or the inactivated virus...

www.thelancet.com

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Ben Cowling

@bencowling88

2 years

Same policy should apply to arriving travelers for consistency

Aaron Busch

@tripperhead

2 years

🚨 Head of the Communicable Disease Branch of the Centre for Health Protection of the Department of Health, Dr Chuang Shuk-kwan: For close contacts from case #12924 onwards, quarantine will be 14 days in a quarantine centre, followed by 7 days home isolation. Test on Day 19.

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Ben Cowling

@bencowling88

2 years

My article with Theo Chan published today in Mingpao (in Chinese) argues that while COVID vaccines should be *recommended* for younger adults in HK, we believe there is insufficient justification at present to *mandate* vaccination in this group … (1/24)

高本恩、陳德光：評新冠病毒疫苗通行證政策 - 20220516 - 觀點

【明報文章】新冠病毒疫苗通行證措施將於5月31日進入第三階段，除新冠病毒康復者及獲豁免人士外，屆時所有12歲或以上人士必須接種最少兩劑疫苗，並於接種兩劑滿6個月後接種第三劑，方可進入指定處所。當年輕成年人日常生活必須使用疫苗通行證，包括上學或上班，令他們幾乎不能拒絕接種，政策本質無異強制接種。

news.mingpao.com

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Ben Cowling

@bencowling88

2 years

In August 2021 we reported compelling evidence that quarantine for Delta can safely be shortened from 21 days to 10 days Omicron latent period is likely even shorter than Delta latent period In January 2022, 5 months later, HK finally shortens quarantine from 21 days to 14 days

Ben Cowling

@bencowling88

3 years

While there's been discussion about the incubation period in terms of quarantine duration, what we really need to know is the /latent period/. Our results indicate that a 10-day on-arrival quarantine for vaccinated persons can minimise the risk of Delta introductions (16/16)

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Ben Cowling

@bencowling88

4 years

New preprint: "Impact of changing case definitions for COVID-19 on the epidemic curve and transmission parameters in mainland China"

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Ben Cowling

@bencowling88

1 year

Really difficult to see the rationale for a mask mandate at this point Mandate only justified if (1) high masking rate is essential for protecting public health plus (2) masking rate will be low without a mandate.

Aaron Busch

@tripperhead

1 year

Secretary for Health, Professor Lo Chung-mau: I can't stress enough the importance of face masks. Even if the mask mandates is dropped, I'm sure many of the public will continue to wear them.

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Ben Cowling

@bencowling88

2 years

Thread on our new preprint (not yet peer reviewed) on the low but non-zero risk of COVID-19 transmission in quarantine hotels in Hong Kong, with @dcadam @gmleung @worldepidemic and other colleagues (1/32)

Within-hotel transmission of SARS-CoV-2 during on-arrival quarantine in Hong Kong

Background On-arrival quarantine has been one of the primary measures used to prevent the introduction of COVID-19 into Hong Kong since the start of the pandemic. Most on-arrival quarantines have...

www.medrxiv.org

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Ben Cowling

@bencowling88

4 years

(4/7) In our analysis of the first wave, we estimated that Rt rose above 2 in late March. This occurred even though we were doing a lot of testing and contact tracing, everyone was wearing face masks, schools were closed, and mass gatherings discouraged.

Ben Cowling

@bencowling88

4 years

(7/10) Almost everybody in Hong Kong was wearing masks in public throughout the epidemic. But there was evidence of community spread in early March, despite this universal masking and test+trace.

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Ben Cowling

@bencowling88

2 years

I think this is very wishful thinking Look at the near-vertical epidemic curves of Omicron in most other countries. Omicron is _much_ more transmissible than previous strains Test and trace won't break every transmission chain, even when done as well as it's done in Hong Kong

RTHK English News

@rthk_enews

2 years

A respiratory disease expert says there is hope that #HongKong can terminate the transmission of #Omicron before the Chinese New Year #COVID19

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Ben Cowling

@bencowling88

2 years

From the SCMP article earlier today, I was surprised at the prediction of 10,000 patients needing hospitalization. The level of peak incidence would have to be very high to result in 10,000 patients needing hospitalization, now that we have high vaccine coverage and some ...(1/4)

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Ben Cowling

@bencowling88

3 years

@tripperhead This is ridiculous I hope it doesn't also apply to "re-positives", that would be even more ridiculous

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Ben Cowling

@bencowling88

2 years

@tripperhead How many deaths have there been in people under hotel quarantine? I would imagine more than just this one

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Ben Cowling

@bencowling88

3 years

@tripperhead If we were only using BioNTech or other highly effective vaccines, and not using Sinovac, it would be easier to propose dropping quarantine for fully vaccinated persons

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Ben Cowling

@bencowling88

3 years

Thread on “sustainable endemicity” versus “ZeroCovid” as alternatives for Hong Kong. Key point, if aiming for “sustainable endemicity”, extending quarantines should only be a short-term measure. Tighter domestic and border measures would be needed to sustain ZeroCovid (1/21)

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Ben Cowling

@bencowling88

1 year

@Birdyword @tripperhead There is no flu "season" in Hong Kong, we can have influenza epidemics at any time of the year. Flu is winter-seasonal in temperate climates, but doesn't tend to have strong/predictable seasonality in subtropical areas like HK

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Ben Cowling

@bencowling88

4 years

Serial interval of SARS-CoV-2 was shortened over time by nonpharmaceutical interventions

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Ben Cowling

@bencowling88

4 years

Our work on superspreading has just been published , the preprint was posted a few months ago.

Clustering and superspreading potential of SARS-CoV-2 infections in Hong Kong

Nature Medicine - Cases linked to superspreading events are estimated to account for 80% of all local transmission of SARS-CoV-2 in Hong Kong in a study with implications for public health policies.

www.nature.com

Ben Cowling

@bencowling88

4 years

(6/10) In our other preprint on superspreading we reported just one example of a 'failure' of quarantine – a close contact was quarantined without symptoms but had already passed on infection to his wife (footnote 1 in Figure 3 of that preprint)

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Ben Cowling

@bencowling88

1 year

@tripperhead I agree and Hong Kong could have done all of this more than 6 months ago

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Ben Cowling

@bencowling88

6 months

Fantastic opening to our 3-day international conference this morning #immunity2023 with many excellent presentations including opening talks by Malik Peiris and Maria Van Kerkove

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Ben Cowling

@bencowling88

2 years

Fascinating article well worth a read: "The unintended consequences of COVID-19 vaccine policy: why mandates, passports and restrictions may cause more harm than good" by an international group of authors in BMJ Global Health

The unintended consequences of COVID-19 vaccine policy: why mandates, passports and restrictions...

Vaccination policies have shifted dramatically during COVID-19 with the rapid emergence of population-wide vaccine mandates, domestic vaccine passports and differential restrictions based on vaccin...

gh.bmj.com

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Ben Cowling

@bencowling88

3 years

Are you sure it’s can’t have both? Seems more like can’t have either of them…

Aaron Busch

@tripperhead

3 years

More: Businesses in HK want access to the mainland and overseas travel, but can't have both.

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Ben Cowling

@bencowling88

3 years

Starting enrolment today at Ap Lei Chau community vaccination centre for our study of individual and population immunity to #COVID19

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Ben Cowling

@bencowling88

1 year

Influenza is not strongly winter-seasonal in Hong Kong. We have had large summer flu seasons before. Indoor mask mandate should only be a measure of last resort during a v large epidemic, if voluntary mask use low. Shouldn't be a permanent rule. Outdoor mask mandate has no basis

Aaron Busch

@tripperhead

1 year

Government advisor Professor Ivan Hung says he expects the government to relax outdoor mask mandates by next summer. This is the same Professor Ivan Hung who said he expected the government to relax mask mandates by last summer.

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Ben Cowling

@bencowling88

3 years

My op-ed in Mingpao explains the likely threshold for herd immunity is high because #COVID19 is so easily spread. It is unlikely that we could reach herd immunity unless we vaccinate at least 2/3 of the population with highly effective vaccines. (1/10)

高本恩：後疫苗時代香港抗疫模式的3個選項 - 20210226 - 觀點

【明報文章】去年3月11日，世衛宣布新型冠狀病毒（SARS-CoV-2）全球大流行。一年快將過去，和世界各地相比，香港的疫情算是控制得不錯，這都是有賴香港市民的迅速反應和政府適時實施的各項抗疫措施，讓疫情在早期被遏阻而不至失控。抗疫一年，隨着疫苗的研發、生產及廣泛使用，估計大家對未來還是充滿着疑問吧！接種疫苗好嗎？疫苗安全嗎？接種後我們期盼的「疫前日常」會否得以恢復？抑或我們仍將會面對一個全...

news.mingpao.com

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Ben Cowling

@bencowling88

4 years

(8/10) Community measures were important in suppressing transmission. Work-at-home was implemented for civil servants and many private businesses in February, stopped in March, and re-implemented later in March. We estimated this reduced transmission by 67% when in place.

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Ben Cowling

@bencowling88

4 years

THREAD .. It's so difficult trying to keep up with changes in case definitions. Based on the experience with SARS, two classifications helped greatly: "suspected case" and "probable case"

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Ben Cowling

@bencowling88

2 years

With an exponential increase in infections indicated by the trend in unlinked cases, it would be reasonable to expect a large jump in cases when testing picks up after the Lunar New Year (1/14)

富士山在住

@Fujisan12388

2 years

@tripperhead Exponential regression of local unknown source cases CASES = 0.9879 * 1.2763^DAY

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Ben Cowling

@bencowling88

4 years

(7/10) Almost everybody in Hong Kong was wearing masks in public throughout the epidemic. But there was evidence of community spread in early March, despite this universal masking and test+trace.

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