Re-infection data for SARS-CoV2 / vaccine viability

Question

It seems that the efficacy (and safety) of the current vaccine candidates has not been tested beyond 2 months duration [1]. However, there have been numerous re-infections with SARS-CoV2 in a town near me (Germany, population ~ 90K, 3000 infected, 9 re-infected) alone. Current state of peer reviewed information is lagging behind - there are less then 7 reported re-infections globally.The reinfection cases by SARS-CoV2 in the German town happened 5 months after initial exposure. No genomic analysis data is available due to the constrained resources of the public health departments. Testing and tracking has been done thoroughly in Germany until now that the capacity gets overwhelmed by the rapid growth of infections.Could perhaps someone (qualified) elaborate whether the vaccines will work in the long term if they have not been tested beyond 2 months time, and re-infection has been reported occurs in the wild after five months? I am aware that the reinfection cases are quite low at the moment - however, I am wondering how the virus evades our immune system so well.Is there any more data available on reinfections? The RKI [3] in Germany is just now acknowledging the data internally and is going to start a wider study.---[1] DOI: 10.1056/NEJMoa2034577 - "Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine" (2020)[2] source: internal public health department data from Germany (prefer not to disclose in public)[3] https://www.rki.de/

sbinthree · Accepted Answer

The half life of the antibodies averages six months but varies. It's not as severe at diseases like smallpox where a single exposure results in antibody production for life. So our body will make energy trade offs by ramping down antibody production, including to zero. Antibodies aren't the only immune response, you can also "train" your T cells. It's the difference between having a team of soldiers train for a particular enemy, vs. training for "enemies at large". It is likely that the first exposure would lead to the most serious infection, because of the delay in the short term immune response due to novelty. This is why people have a really bad week two with covid (delay followed by panic). It could end up being like the flu, where due to mutation and waning immune response getting the vaccine annually makes sense. It's unlikely we would need the vaccine every 6 months for healthy people.