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.
A representative survey of US adults in mid-2022 found that 7% had long COVID (4-week definition; using questions developed by the UK’s Office for National Statistics).
I've not commented on this study so far, because it's uncertain what the findings mean. But I've seen some commentary that's definitely wrong and causing a lot of unnecessary concern. Further study is needed, but here's why I don't think people should be worried. 🧵
Second, this has nothing to do with IgG4-Related Disease, where IgG4 antibodies are thought to be an epiphenomenon. That is, they are an effect of the disease, not its cause.
China’s decision to not just abandon zero COVID but to embrace an extreme “let it rip” policy is a catastrophe for both the Chinese people and the world. It will leave millions dead or disabled, badly damage the global economy, and may spawn dangerous new coronavirus variants. 🧵
The scale of the disaster is hard to imagine. There are an estimated 1,000,000 new infections and 5,000 deaths each day.
Not that you'd know this from the official statistics, which are no longer reported daily. The official death toll stands at 5,242. dw.com/en/china-stops…
The huge number of infections is reflected in the fact that China is exporting COVID-19 cases again. And not just exporting a few, either.
A danger of giving up trying to control SARS-CoV-2 is that we increase the probability of a low likelihood but high impact event occurring. One such risk is recombination between SARS-CoV-2 & MERS. This could theoretically occur if someone were coinfected with these two viruses.
MERS has a case fatality rate of 36%, while SARS-CoV-2 is highly transmissible. A recombinant that shared some of these properties could potentially be catastrophic.
MERS hasn't gone away. According to the European Centre for Disease Prevention and Control, 6 MERS cases were recorded in 2022. All occurred in the Middle East, all were primary cases, and all but one of the infected people reported contact with a camel. ecdc.europa.eu/en/middle-east…
An important new retrospective study of people who tested positive for COVID-19 in Ontario, Canada between the start of the pandemic and early 2021, has found that about 1% of these experience substantial post-infection morbidity. 🧵 cmaj.ca/content/194/40…
In early 2022, about 45% of Canadians had a recent SARS-CoV-2 infection.
The authors write that over the next year, about 1% of these people will likely be admitted to hospital roughly 1 week longer than those who didn’t have COVID-19.
They will use 6.6% of pre-pandemic hospital bed-days at a time when almost 20% of hospitals have already averaged more than 100% annual occupancy rates.