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Dr Zoë Hyde Profile picture
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5 Apr, 12 tweets, 4 min read
(1/12) The Brazilian #COVID19 variant is up to 2 times more transmissible, more likely to cause serious illness in young people, and may evade immunity.

Worryingly, it’s starting to spread rapidly in British Columbia, Canada. 🇨🇦

A thread summarising the latest evidence. 🧵
(2/12) Previous research suggested the variant was 40 to 120% more transmissible, and may be able to reinfect people more easily.

Mortality appeared 10 to 80% higher, although it was unclear if this reflected hospitals being overwhelmed with cases.
(3/12) Two new pre-print studies (interpret them carefully) provide more evidence the variant is more virulent.

A study conducted in Brazil’s Amazonas state found that women and young people were more seriously affected once the variant became common.
(4/12) Mortality was 24% higher in men & 63% higher in women.

Risk was markedly increased in young adults, with those aged 20-39 years being 2.7 times more likely to die.

However, stretched hospital capacity almost certainly still played some role.
preprints.scielo.org/index.php/scie…
(5/12) A second study from Brazil’s Paraná state also found that hospitalised young adults aged 20-29 years were approximately 3 times more likely to die.
medrxiv.org/content/10.110…
(6/12) Further evidence that the Brazilian variant is genuinely more transmissible and more virulent comes from Canada.

Situation reports from British Columbia show case numbers of the Brazilian variant are increasing more rapidly than other variants.
bccdc.ca/health-info/di…
(7/12) Case numbers by week:

Week 7: UK: 157; SA: 23; Brazil: 0.
Week 8: UK: 502; SA: 33; Brail: 11.
Week 9: UK: 819; SA: 40; Brail: 21.
Week 10: UK: 1238; SA: 41; Brazil: 84.
Week 11: UK: 1907; SA: 48; Brazil: 269.

(NB: a small number of UK and SA cases are overseas-acquired.)
(8/12) Healthcare workers are already reporting an increase in young people arriving at hospital very unwell.

(This may not exclusively reflect the Brazilian variant, however.)
(9/12) There is also evidence to suggest that vaccine efficacy may be reduced against the Brazilian variant, although it’s important to remember that the vaccines likely still prevent serious illness in the overwhelming majority of people.
(10/12) What does this mean for vaccination? Should you still get vaccinated if efficacy is lower? Absolutely! More than ever!

The vaccines will protect you, but some vaccinated people might still be able to get a (hopefully mild) infection & transmit the virus to other people.
(11/12) That means public health measures should continue until everyone has had a chance to get vaccinated.

For example, you should keep wearing a mask until there is no danger of passing the virus to someone who might get seriously ill.

And ventilate - SARS-CoV-2 is airborne!
(12/12) These findings also reinforce the importance of trying to suppress transmission as much as possible, rather than trying to “learn to live” with the virus.

Don’t think the tragedy unfolding in Brazil can’t also happen to your country.

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Dr Zoë Hyde Profile picture
2 Apr
The California variant (B.1.427/B.1.429), appears more transmissible and possibly more virulent (but less than the UK variant).

Concerning new data suggest vaccine efficacy against symptomatic disease might be reduced (though probably not as much as the South African variant).
However, vaccines have better efficacy against severe disease than mild-to-moderate disease.

It’s therefore likely that efficacy against severe disease will be largely preserved, but we may see reduced protection with regard to transmission.
There is also the potential for reinfections to be more common with this variant, particularly for people who had only very mild COVID-19, and did not develop much in the way of neutralising antibodies.
Read 4 tweets
Dr Zoë Hyde Profile picture
1 Apr
Updated Pfizer results have been released.

➡️ 91% (95% CI 89-93%) efficacy against symptomatic infection.

➡️ 100% (88-100%) efficacy against severe disease as per the CDC definition (based on 32 cases); 95% (71-99%) efficacy as per FDA definition (22 cases, 1 in vaccine group).
Additionally, Pfizer also reported data from South Africa, in which 800 people received the vaccine.

Nine cases were detected in the placebo group, 6 of which were the South African variant.

No cases were detected in the vaccine group.
This provides tentative evidence that the Pfizer vaccine may be effective against the South African variant, although the confidence interval is wide (53-100%).

Link to announcement: pfizer.com/news/press-rel…
Read 4 tweets
Dr Zoë Hyde Profile picture
1 Apr
Today, the UK’s Office for National Statistics released an enormously important report on long COVID.

The data now have a control group.

Over 1 in 10 people (14%) have persistent symptoms at 12 weeks. This is 8x higher than controls.

Look at the children’s data: 7-8% affected!
We can clearly see the difference between people who have long COVID, and people who are controls, in this graph showing the proportion of people with persistent symptoms at the 5-week mark.

Blue = tested positive.
Green = controls.
The proportion of people who had persistent symptoms was lower at 12 weeks, which suggests improvement in many people.

This is to be expected.

However, a substantial proportion of people appear to be left with protracted symptoms.
Read 5 tweets
Dr Zoë Hyde Profile picture
30 Mar
It's increasingly clear this is a real & very serious adverse effect.

In much of the world, use of the AstraZeneca vaccine still makes sense. The benefits still outweigh the risks.

That's not the case in Australia, and we should pivot to an alternative vaccine. #auspol
Australia doesn't have widespread community transmission. That means the AstraZeneca vaccine could harm more people than it helps - at this point in time.

This picture could of course change, if Australia were to experience a major wave.
But what about Europe, or the Americas? A case could be made for continuing to use the vaccine, but restricting its use to older age groups, who seem less likely to experience this adverse effect.

This is now the case in France or Germany.
Read 6 tweets
Dr Zoë Hyde Profile picture
29 Mar
The #Brisbane outbreak is the result of incompetence.

Doctors aren’t getting airborne PPE (P2/N95 respirators). If distance can be maintained, masks aren’t required at all!

SARS-CoV-2 is airborne, so why is Queensland following substandard guidance?
#BrisbaneLockdown #auspol
Additionally, the doctor at the centre of the Brisbane outbreak should have been vaccinated.

Currently, the greatest risk to Australia comes from overseas arrivals. We need to put a protective ring around the quarantine system, by vaccinating these Australian workers first.
Here’s a link to the infection control guidelines for Queensland.

Healthcare workers are routinely given inadequate protection - or perhaps no protection at all, if distance can be maintained!

This is inadequate for an airborne virus like SARS-CoV-2.
health.qld.gov.au/__data/assets/…
Read 9 tweets
Dr Zoë Hyde Profile picture
24 Mar
I've just seen an editorial calling for people to be more polite on social media. Sounds good, doesn't it? I agree.

But there's some background to this piece that I think people ought to be aware of, because it looks to me like an attempt to re-write history.
In June last year, one of the authors of the editorial falsely accused me of misrepresenting the findings of a study.

Here's how the interaction played out:
This strikes me as hypocritical, given his own conduct.

In this study, Dr Munro said there was "no increase in death". That was so for younger adults, but not those aged >65, who had an increased risk of death from COVID-19.

That's quite an omission.
Read 10 tweets

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