J&J and Delta update

Link: https://yourlocalepidemiologist.substack.com/p/j-and-j-and-delta-update



Neutralizing antibodies in a lab is difficult to map to real world efficacy. Thankfully, some scientists figured out a mathematical model (here). Using their model, this means the efficacy of J&J would be around 55-60% against symptomatic disease. It will still work well against severe disease.

In the same update, J&J said their vaccine continues to work over time, with strong responses for up to 8 months. This is because there’s only 8 months of data; we are optimistic it will last longer.

Author(s): Katelyn Jetelina

Publication Date: 2 July 2021

Publication Site: Your Local Epidemiologist on substack

Vaccine Efficacy and the Immunity Time Spans

Link: https://polimath.substack.com/p/vaccine-efficacy-and-the-immunity



Let’s refer back to the Pfizer study submitted to the FDA. In that study, 18,555 people were vaccinated and 18,533 people received the placebo injection. In these groups, 7 days after the second dose was administered, we saw that the vaccinated group got infected at only 5% the rate that the placebo group was infected.

Furthermore, this is the number of cases we see over the course of a two month study. So those 9 people out of 18,555 were not symptomatic and infectious that whole time, but only for a few weeks.

So, to take CNN’s example and re-imagine it for the reality we have with this data.

Let’s say 1 million people are travelling. If everyone is unvaccinated (and the window of infection is roughly one week), there will be about 1,100 infected travelers.

If, however, everyone is vaccinated, there will be about 60 infected travelers and their chance of infecting you (my dear vaccinated friend) is reduced substantially.

Author(s): PoliMath

Publication Date: 13 April 2021

Publication Site: Marginally Compelling on substack