1/ Our team has just published the first #COVID19 vaccine effectiveness estimates against the Omicron vs Delta variant after 2 Pfizer or 2 AZ vaccine doses, and after a Pfizer booster 6 months later.

Here is a quick summary …🧵

More details here 👉 assets.publishing.service.gov.uk/government/upl…
2/ Effectiveness against #covid19 consistently lower for Omicron vs Delta at all timepoints. For Omicron: from 15 weeks after dose 2, little/no effect with AZ & <40% with Pfizer. A Pfizer booster 6 months after 2 AZ or 2 Pfizer doses significantly ⬆️ VE from 2 weeks post-booster
3/ The report also contains early household transmission risk assessment for Omicron vs Delta: 19% of Omicron index cases gave rise to a secondary household case vs 8.3% of Delta index cases 👉household transmission odds were 3.2-fold higher for Omicron than Delta @kallmemeg
4/ Important to note that these are very early analyses with very small numbers of Omicron cases in England. Better quality data with more robust estimates will emerge with time. But these early data are consistent with everything we know about the Omicron variant so far

…/End

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More from @ShamezLadhani

10 Dec
1/ In 2015, the UK became the first country to implement a protein-based Meningococcal B vaccine (4CMenB) into the infant immunisation programme

Here, we show that vaccinated kids are now infected with different MenB strains than unvaccinated kids…🧵

👉journalofinfection.com/article/S0163-…
2/ We recently showed that the UK 4CMenB infant immunisation programme is highly effective in preventing #meningitis/septicemia caused by group B meningococcal bacteria (MenB), the predominating serogroup (strain) causing invasive disease in Europe

👉 nejm.org/doi/full/10.10…
3/ Since then we also showed 4CMenB can also protect against other meningococcal serogroups such as MenW because the proteins in the 4CMenB vaccine are present on the surface of all meningococci (not just MenB)

👉 academic.oup.com/cid/article-ab…
Read 6 tweets
8 Dec
“Acute and persistent symptoms in children with SARS-CoV-2 infection”

Our national case-control study on “post-acute #COVID19 syndrome” using PCR-testing is now published in Clinical Infectious Diseases @OUPAcademic

👉 academic.oup.com/cid/advance-ar…
2/ We used national testing data to compare a range of different symptoms at the time of infection & 1 month later in 2-16 year-olds with PCR-confirmed #SARSCoV2 infection (cases) compared to matched children with a negative #SARS_CoV_2 PCR test (controls) in January 2021 Image
3/ The most important message is that nearly all kids with #COVID19 recovered quickly without having to see a doctor or go to hospital.

After 1 month, 93.3% of kids with symptomatic #COVID19 had recovered vs 96.8% of symptomatic kids who tested negative for #SARSCoV2 (p=0.24)
Read 8 tweets
25 Nov
1/ Our preprint on #SARSCoV2 antibody responses in UK adults receiving a #COVID19 vaccine booster with the Pfizer vaccine at least 6 months after primary immunisation with Pfizer or AZ vaccine, which was given at an extended interval (8-12 wks) … 🧵

👉 medrxiv.org/content/10.110…
2/ We recruited adults aged 50+ years when they became eligible for their #COVID19 vaccine as part of the UK National Immunisation Programme. Participants provided regular blood tests for #SARS_CoV_2 antibodies at multiple intervals, including before & after the booster dose.
3/ 3 groups were assessed: (i) 2 Pfizer doses <30 days apart (Pfizer-control), (ii) 2 Pfizer doses ≥30 days apart (Pfizer-extended) or (iii) 2 AZ doses ≥30 days apart (AZ-extended) in London, England. Spike protein antibodies were compared before and 2-4 weeks after the booster
Read 9 tweets
6 Oct
1/ Comparison of Symptoms and RNA Levels in Children and Adults With SARS-CoV-2 Infection in the Community Setting

👉 @JAMAPediatrics paper comparing kids vs adults - most findings are as expected but good to see them confirmed in a large study… 🧵

👉jamanetwork.com/journals/jamap…
2/ This cross-sectional population-based survey included a convenience sample of 37,000 kids & adults in King County, Washington, who enrolled online for home self-collection of upper respiratory samples for SARS-CoV-2 testing from Mar-Nov 2020
3/ 37,067 samples were tested & 673 (1.8%) were #sarscov2 positive (1.6% in adults, 3.4% in kids)

Most kids (80%) had a known SARS-CoV-2 +ve contact, & most contacts (68%) were in the same household

But only 41% of SARS-CoV-2 +ve adults (41.4%) reported any known +ve contact
Read 9 tweets
17 Sep
1/ Household transmission of #SARSCoV2 in children & adults

This new @PHE_uk study was pre-Alpha, pre-Delta & pre-vaccine but provides important insight into household infection & transmission risks in kids & adults

Here’s what the study found … 🧵

👉 journalofinfection.com/article/S0163-…
2/ The study followed up 452 household members of 181 PCR-confirmed adult & child cases in England during Mar-Nov 2020.

Nasal swabs taken for #SARSCoV2 PCR at baseline & Day 7.

#SARSCoV2 Antibodies tested at baseline & Day 35 to detect symptomatic + asymptomatic infection Image
3/ 91/431 (21%) contacts were PCR +ve & 180/383 (47%) were antibody +ve at day 35 👉 194/431 (45%) contacts had PCR +/- antibody evidence of infection

After excluding 55 households with prior/co-primary cases & PCR -ve asymptomatic contacts, 75/248 *(33%)* contacts were infected
Read 8 tweets
14 Sep
1/ How long do 2 doses of #COVID19 vaccines protect for? Who needs booster vaccinations?

Our team @phe_uk have just published a pre-print on vaccine effectiveness (VE) and duration of protection after 2 doses of Pfizer and AZ vaccines in adults … 🧵

👉 khub.net/documents/1359…
2/ We now have data for ~6 months post-vaccination & compare VE by age, comorbidity & #sarscov2 strain (Alpha/Delta)

We used a test-negative case-control design to estimate VE after 2 doses against PCR-confirmed disease, hospitalisation within 14d of PCR test & death within 28d
3/ In this analysis, 2 million adults (38.7%) had 2x AZ, 1.7 million (31.7%) had 2x Pfizer, 124k (2.4%) had 2x Moderna & 10k (0.2%) had mixed/other

There were 1.5 million cases (544k Alpha, 895k Delta, 37k other/unknown) & 3.8 million negative tests from 3.3 million adults
Read 11 tweets

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