(1/7) Report by Ministry of Health, Israel, showing children more likely to be infected than adults, are mostly asymptomatic, can be superspreaders, that school clusters spread into the community, and that school reopening accelerated the epidemic there.
gov.il/BlobFolder/rep…
(2/7) As shown in the figure below, children were more likely to test positive than adults (8% vs. 6% of all PCR tests conducted in Israel).

Children were also more likely to test positive for #SARSCoV2 antibodies than adults (7% vs. 2 - 5%).
(3/7) Most children with #COVID19 were asymptomatic (51-70%).

As shown in the figure below, children of pre-school & primary school age were more likely to be asymptomatic than older children.

The top (pink) bar indicates the proportion who were asymptomatic in each age group.
(4/7) Across Israel, 350 people who infected at least 10 others were identified. Of these superspreaders, 17 (5%) were children.

Seven children each infected 10 people, three children each infected 12 people, and one child infected 24 people.
(5/7) Infections in schools ultimately spread into the wider community.

In this figure, a #COVID19 cluster at a primary school is depicted. The cluster initially involved 5 teachers and 20 students, and ultimately affected 79 people.
(6/7) As shown in the figure below, there was a marked rise in new cases following the reopening of schools on 1 September.

However, schools were not the only factor, as cases were already rising in the oldest age group (15-17 years).
(7/7) The authors of the report conclude that the reopening of schools may accelerate the spread of #SARSCoV2, unless community transmission is low.

The authors recommend the return to schools be gradual.
Addendum: It has been pointed out to me that schools for the Ultra-Orthodox community reopened on 21 August, slightly before the rest.

This may explain the earlier rise in cases which was most apparent in the 15-17 year age group.

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More from @DrZoeHyde

28 Oct
My paper on #COVID19, children, and schools is now published, with new material added.

"We can no longer afford to overlook the role children play in transmission if we hope to contain the virus."

Precautions must be put in place in schools. #auspol
onlinelibrary.wiley.com/doi/full/10.56… Image
Important note:

The figure quoted for mortality in the paper is the case fatality rate, which is applicable to hospitalised children (a thankfully uncommon occurrence).

The infection fatality rate (mortality among all children who become infected) is probably 1000 times lower.
However, infections in children remain extremely important, because children can transmit the virus to older adults and other at-risk persons, who have far greater risk for mortality.

We will also not be able to control the pandemic unless we address transmission by children.
Read 5 tweets
25 Oct
(1/5) Study showing that school closures were associated with a marked reduction in the common cold in adults in the UK.

When schools reopened, rhinovirus detections surged. Physical distancing measures in schools are inadequate to prevent transmission.
thelancet.com/journals/lanre…
(2/5) In this study, patients admitted to hospital between March and September 2020 in Southampton were screened for rhinovirus.

The results were compared against data for 2019.

There was a marked decrease in rhinovirus in 2020, which was associated with school closures.
(3/5) When schools reopened, rhinovirus infections in adults increased, and became comparable to the previous year.

This suggests children are a major driver of the common cold, and that #COVID19 precautions in schools are inadequate to prevent transmission of rhinovirus.
Read 5 tweets
20 Oct
(1/6) A new pre-print study (interpret carefully) describes *in vitro* evidence of antibody dependent enhancement (ADE) after natural infection with #SARSCoV2 in some people. ADE is when antibodies make a second infection worse.
scmp.com/news/china/sci…
(2/6) If ADE occurs, it is most likely to happen late after recovery when levels of neutralising antibodies have waned.

Here’s the actual study:
medrxiv.org/content/10.110…
(3/6) This review describes what ADE is, how it can occur, and what we know about ADE and other coronaviruses so far.

There is no evidence of ADE occurring with any #COVID19 vaccine under development yet.
stm.sciencemag.org/content/early/…
Read 6 tweets
14 Oct
This article is damning. I strongly recommend reading it to the end.

“The Swedish way has yielded little but death and misery. And, this situation has not been honestly portrayed to the Swedish people or to the rest of the world.”
time.com/5899432/sweden…
Sweden:

“Only 13% of the elderly residents who died with COVID-19 during the spring received hospital care”
Sweden:

“Policymakers essentially decided to use children and schools as participants in an experiment to see if herd immunity to a deadly disease could be reached”
Read 6 tweets
14 Oct
(1/8) Contact tracing study from Brunei. Household contacts of symptomatic cases were more likely to be infected than those of asymptomatic cases (14.4% vs. 4.4%). Children and adults were similarly likely to be infected (3.4% children vs. 2.8% adults).
wwwnc.cdc.gov/eid/article/26…
(2/8) This study describes the contract tracing which occurred after 19 people who attended a religious gathering in Malaysia (in which a superspreading event occurred) returned to Brunei.

51 cases were identified via contact tracing (plus 1 further case identified separately).
(3/8) A total of 1,755 contacts were traced, of which 381 were persons aged <18 years, and 1,366 were adults. Age was not recorded for 8 contacts.
Read 8 tweets
13 Oct
(1/4) Study of a #COVID19 cluster at a family gathering, in which a 13-year old girl was the index case. Despite being only mildly symptomatic, she likely transmitted the virus to 11 of 19 family members (58%). One person was hospitalised, but recovered.
cdc.gov/mmwr/volumes/6…
(2/4) The index case had been exposed to a large #COVID19 outbreak away from home. After returning home, she was tested with a rapid antigen test (four days after exposure) which was negative. She was asymptomatic at the time of the test, and developed symptoms two days later.
(3/4) Rapid antigen tests are generally less sensitive than a PCR test, meaning that not all infections may be detected.

Anyone who is exposed to a person with #COVID19 should self-isolate for 14 days, even if their test result is negative. It may be a false negative.
Read 4 tweets

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