(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.
(4/8) Attack rates were as follows:

Children: 13 cases / 381 contacts = 3.4%
Adults: 38 cases / 1,366 contacts = 2.8%
(5/8) The overall household attack rate was 10.6% compared to <1% for workplaces and social settings. Spouses had the highest attack rate.

Close-contact markedly increases the risk of transmission.
(6/8) Of the 51 cases among contacts:

5 were asymptomatic (9.8%)
15 were pre-symptomatic (29.4%)
31 were symptomatic (60.8%)
(7/8) Within the household, the attack rate for contacts of symptomatic cases (14.4%) was higher than for contacts of pre-symptomatic (6.1%) or asymptomatic cases (4.4%).
(8/8) However, while the attack rate for contacts of asymptomatic cases was lower than that of symptomatic cases, it was not negligible.

This suggests that asymptomatic #COVID19 cases still pose a significant transmission risk to others.

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More from @DrZoeHyde

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
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
3 Oct
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).
3. Another large antibody study has shown that children and adults are similarly likely to be infected.

Importantly, young children and teenagers were just as likely to be infected.
Read 33 tweets
30 Sep
(1/4) Study of #SARSCoV2 transmission on a 5-hour flight from Sydney to Perth. There were 11 people considered infectious on board. Eight probable & 3 possible secondary cases resulted from the flight. 27% sat more than 2 rows away, & 64% had window seats.
wwwnc.cdc.gov/eid/article/26…
(2/4) Two of the secondary cases who sat in window seats never left their seat during the flight. This, and the fact that 27% of secondary cases sat more than 2 rows away from index cases suggests aerosol transmission may have occurred.
(3/4) Index cases didn’t seem equally infectious, and transmission was only detected in the mid cabin. No secondary cases were detected in passengers sitting in the aft cabin, despite infectious passengers being in this area. This raises the possibility of a superspreading event.
Read 4 tweets
29 Sep
(1/7) Study of #COVID19 in US children. 277,285 cases were reported between 1 March and 19 September. Incidence higher in adolescents compared to young children (although more adolescents were tested). 1.2% were hospitalised (0.1% ICU), and 0.02% died.
cdc.gov/mmwr/volumes/6… Image
(2/7) The overall average weekly incidence was as follows:

Ages 5-11 years:
19 cases per 100,000 persons

Ages 12-17 years:
37 cases per 100,000 persons

However, more older children were tested than younger children. Image
(3/7) Overall, adolescents were more likely to test positive than younger children, but this was not the case in all regions.

In some regions, there was no difference in the proportion of younger and older children testing positive. ImageImageImageImage
Read 7 tweets
24 Sep
(1/4) More on the recent reinfection cases from India. Two papers (one of which is a pre-print) describe the cases.

An insufficient antibody response might explain at least some of the cases, which were mild or asymptomatic the first time.

H/T: @vinodscaria and @swapneilparikh.
(2/4) In the first study, cases were detected in two healthcare workers during routine surveillance.

The workers were asymptomatic for both infections, which were 108 and 111 days apart.

Viral loads were higher the second time.
academic.oup.com/cid/advance-ar…
(3/4) In the second paper, 4 cases in healthcare workers are described.

The cases were mild or asymptomatic the first time, and marginally worse the second time with longer illness.

The interval between the infections was 16, 53, 63, and 65 days.
papers.ssrn.com/sol3/papers.cf…
Read 4 tweets

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