1. Updated thread on children & #COVID19 summarising the most recent research.
Summary: further evidence children & adults are equally susceptible & equally likely to transmit; school clusters are increasing; precautions needed in #schools. #edutwitter#kinderen#Schulen#auspol
2. First, a recap, showing the risk associated with schools is largely dependent on community transmission.
If it is low (for example, at a level contact tracing can handle) then schools are low-risk (although precautionary measures are still needed).
6. Emerging data continue to suggest that children are as infectious as adults.
7. In the largest contact tracing study to date, a similar proportion of the contacts of child index cases and the contacts of adult index cases were infected.
9. Although it's not possible to say with certainty who infected whom in these studies, they strongly suggest that children do transmit the virus at clinically meaningful rates.
10. Even the youngest children can transmit the virus.
In this study, young children transmitted the virus to one-quarter of their household contacts.
Two out of three completely asymptomatic children transmitted the virus.
18. This suggests it will be difficult to identify schoolchildren with #COVID19, and that schools will be an ideal environment for the virus to spread because of the number of close contacts that children have.
19. Although many cases in schools have been reported, there have been fewer superspreading events than was initially feared.
However, this doesn’t mean that children don't transmit the virus or that schools are a low-risk environment.
20. Two recent studies have shown that about 70% of infected people don’t seem to transmit the virus to anyone.
See the study below, and also the study described previously in point 7.
21. Exactly why is unclear. Possible reasons include the timing of infection, (lack of) opportunity to transmit, environmental factors that enhance transmission, and individual characteristics.
22. However, the frequency of transmission can be expected to be linked to the level of community transmission.
Higher levels of community transmission mean a greater probability of the virus being introduced to schools.
23. During a period of low community transmission in Germany, there was limited school transmission.
However, precautions were taken, including reducing class sizes by 50%, and regular ventilation of classrooms.
26. Measures must be taken to reduce community transmission, and also to reduce the risk of transmission in schools.
At a minimum, this should include the use of face masks by staff and students (including both primary and high school students), and increasing ventilation.
27. Evidence continues to emerge of aerosol transmission being a major route.
This means that physical distancing - while important - is not sufficient.
Improving ventilation, wearing face masks, and reducing class sizes (if possible) are key.
29. If a school-aged child can safely wear a mask, they should.
Many Asian countries already require schoolchildren to wear masks, such as Singapore.
It is a simple intervention with minimal, if any, harms, as the Asian experience has shown.
30. On the other hand, if children are told they do not need to wear a mask in school and that they are unlikely to transmit the virus there, how can we expect them to behave outside school?
It seems unlikely they will follow precautionary measures. Advice must be consistent!
31. Even though children are far less likely than adults to become seriously ill, they can transmit the virus.
(3/22) Now, on to the paper. It's been argued that children are less susceptible to infection with SARS-CoV-2 than adults and play only a minor role in transmission.
This conclusion is likely premature, because it's often difficult to detect infections in children.
I don't like to dwell on negatives, but something important happened recently that I'd like to make public.
Shortly before Christmas, @mugecevik made a complaint to my university about me. When asked for details, she didn't provide any. My employer took a dim view of the matter.
I thought that was pretty strange, but laughed the matter off. After all, the complaint didn't go anywhere and I was supported by my university.
But last week, she made a complaint to a publisher about an article I recently wrote. It was this article: theconversation.com/herd-immunity-…
She listed an astonishing 12 complaints (yes, 12!), said the article was grossly inaccurate, and asked for the article to be retracted.
However, no errors of fact were identified, so the article has not been retracted.
Historically, I’ve not been a big user of social media. It never really appealed to me.
But in early 2020, I was pretty sure we were facing a pandemic and so started this account to share my thoughts with friends and family.
It got a bit bigger than I expected.
But as this account has grown, it’s taken up more of my time than it did in the beginning.
I don’t plan to stop tweeting any time soon, but I’m going to have to spend a bit less time on here. For one thing, it’s grant-writing season now, and that’s going to occupy me for a bit.
I’ve also begun to see how social media can be quite an addictive medium and I don’t want to get sucked into that. So I’m going to pull back a little in terms of the amount of time I spend on here.
Here’s some good news. In this study of 514 people who received their first Pfizer vaccine dose, those who’d previously been infected showed a superior immune response compared to uninfected people, even if initial antibodies were no longer detectable. eurosurveillance.org/content/10.280…
Research has already shown that the vaccine acts like a super-booster in people who’ve been infected with SARS-CoV-2, suggesting that one dose may be enough for them.
However, it wasn’t clear if this would still apply if the antibodies from infection were no longer detectable.
This study shows that everyone got a boost, even if they no longer tested positive for antibodies.
A limitation is that the study only had 17 people with a previous infection (6 with detectable antibodies, 11 without), but the results are still reassuring.
Thread summarising an important presentation on the AstraZeneca trial results for South Africa.
Key points:
➡️ Efficacy initially seemed to be ~75%, but dropped to 22% against SA 🇿🇦 variant.
➡️ Past COVID-19 (original) doesn't protect against reinfection by the SA 🇿🇦 variant.
This was a relatively small trial with only 1,749 mostly young, healthy participants.
People were given two doses of the vaccine about 28 days apart.
The relatively small number of people in the trial makes it suitable for exploring the efficacy of the Oxford/AstraZeneca vaccine against mild-to-moderate disease only.
The trial lacks statistical power to tell us the efficacy of the vaccine against severe disease.
According to preliminary results seen by the Financial Times, the Oxford/AstraZeneca vaccine does not appear to prevent mild and moderate COVID-19 caused by the South African variant.
While the company believes the vaccine may still prevent severe disease, there are now question marks as to whether it will be sufficient to prevent the debilitating condition known as long COVID, which is common even in mild disease.