Epidemiology

Introduction

• Sebastian Rushworth, (November 2021) :

In early 2021, the Delta variant springs in to existence in India, and rapidly races through the population. Population antibody testing reveals that roughly 50% of India’s population become infected over the course of just a few months, with the proportion of the population with antibodies rapidly rising from 20% to 70%, at which point sufficient population immunity sets in for viral spread to drop down to low endemic levels.

• Sebastian Rushworth(November 2021), on vaccine durability:

This was a registry based study, so it’s not surprising that it is coming out of Sweden. Sweden is generally acknowledged as being better than any other country at collecting and sorting large quantities of population data and using it to produce these types of studies.

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governments had initially set the bar for approving the vaccines at a 50% relative risk reduction. So, if the trials had been required to run for six months before presenting results instead of only running for two months, then the vaccines would have been considered too ineffective to be worth bothering with, an would never have been approved.

Well, that’s not quite true. One vaccine did still provide a better than 50% relative risk reduction at six months – the Moderna vaccine. At four to six months, the relative risk reduction with the Moderna vaccine was 71%. Pfizer was at the same time point only offering a 47% reduction in risk, and AstraZeneca was at that point not doing anything whatsoever to lower risk.

It makes sense that the Moderna vaccine would offer better protection than the Pfizer vaccine. Although the vaccines are virtually identical, the dose in the Moderna vaccine is three times higher. This is likely the reason why Moderna has been associated with much higher rates of myocarditis, which is why it is no longer approved for use in people under the age of 30 here in Sweden.

By the nine month mark, the Pfizer vaccine is no longer offering any protection whatsoever against symptomatic covid-19. Unfortunately, nine month out data isn’t offered for the Moderna vaccine due to the small number of people for whom that information is currently available, but at six months out, the Moderna vaccine’s ability to prevent symptomatic covid-19 had dropped to only 59%.

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there are two possible explanations for the rapidly declining effectiveness of the vaccines. The first is that it’s due to the limited immunity produced by the vaccines themselves, and the second is that it’s due to the continued evolution of the virus and in particular the rise of the delta variant. If the second reason is true, then there is no reason whatsoever to give people boosters, because the boosters won’t do anything to improve immunity.

If the first reason is true, then there is a case to be made for boosters, although it feels pretty absurd to give everyone a booster every four months to protect against a virus that for most people is little more than a cold, that 99,8% of infected people will survive, and for which there is now massive natural population immunity, thanks to all the people who have already had covid. Unlike the short-term protection offered by the vaccines, the protection generated by infection has been shown to be both durable and broad, in spite of junk science claims to the contrary produced by the CDC. There is however a pretty good case to be made for regular boosting of the multi-morbid elderly every four months, preferentially with the Moderna vaccine.

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