CV and mad panic behaviour

[LP]

Where's your data?

The best data is coming out of Europe, in fact some of the European states that were previously skeptics are now lauding vaccination. Even the Danes who officially tried hard to be sceptical about vaccination could only find small percentage changes from the efficacy baselines for both Delta and Omicron. If the vaccines did not work against Omicron the percentage changes would have to be hundreds of percent, as you have to keep in mind the Danes are writing about percentage changes to a figure of about 10 - 15% percent.

Unvaccinated prospective secondary cases had similar attack rates in households with the Omicron and Delta VOCs at 29% and 28%, respectively. However, fully vaccinated individuals had SAR of 32% in households with the Omicron and 19% in households with the Delta VOC. Meanwhile, Omicron rendered a SAR of 25% in booster-vaccinated individuals, whereas Delta correlated to a SAR of only 11% in this cohort.

Seven days after the primary episode, which was considered a positive test result in this study, the cumulative chance of probable secondary cases rose from 33-41% to roughly 87-89%. The chances of secondary infection were higher in cases where the primary case, which was the first individual within a household to test positive, was with the Delta VOC rather than with the Omicron VOC.

So effectively, the same efficacy figures that apply to Delta effectively apply to Omicron.

Listening to the BBC overnight, the COVID report suggests new data coming out will confirm the vaccines efficacy for Omicron is still above 75%, that viral load of Omicron is reduce 1000x in vaccinated people who have had the booster, and that breakthrough infections are 2x more likely to come from an unvaccinated carrier than a vaccinated carrier. (Even though on average people are surrounded by 10x more vaccinated people than unvaccinated, you are still 2x more likely to be infected by the unvaccinated carrier, the risk is not just a function of head count it is also a function of viral load and mutation rates(Each variant VOC has hundreds or thousands of subtypes, the more viral load the more subtypes exist.)) This is interesting because if correct the UK study will confirms modelling studies conducted earlier by ATAGI, that vaccination still has high efficacy against severe disease, and that is exactly how the vast majority of vaccines work.

A mathematical modelling study has examined the relationship between neutralising antibody titres and vaccine effectiveness estimated in epidemiological studies. The investigators predicted that six months after primary immunisation with an mRNA vaccine, efficacy for Omicron is estimated to have waned to around 40% against symptomatic disease, and 80% against severe disease (36.7% [95% CI: 7.7-73], 70.9% [95% CI: 32.9-91.5] and 81.1% [95% CI: 42.1-96] for the AstraZeneca, Pfizer and Moderna vaccines, respectively). A booster dose with an mRNA vaccine has the potential to increase efficacy for Omicron to 86.2% (95% CI: 72.6-94%) against symptomatic infection and 98.2% (95% CI: 90.2-99.7%) against severe infection.