On 21 May 2021 I received my first Covid-19 inoculation, and my vaccination record card indicated that I my appointment for the second injection was 21 days later, on 17 June 2021. Whilst waiting for the second, I was informed by SMS that the interval had been extended to 42 days.
In a huff of anger and frustration, I immediately attempted to verify this unexpected change of procedure, by going to the Pfizer protocol, which still indicated an interval of 21 days. I concluded, without additional verification that this was the fault of the South African Government, who in my opinion, was either running out of second doses, were inept in the rollout, or were trying to achieve partial immunity through this change.
I was wrong. A recent publication, in the process of being peer reviewed suggests that a 42 day interval is the so-called “sweet spot”. Here is the gist of their findings:
Antibody levels in their blood were measured a month after the second vaccine dose.
The findings suggest:
- both short and long dosing intervals of the Pfizer vaccine generated strong immune responses overall
- a three-week schedule generated fewer of the neutralising antibodies that can bind the virus and stop it infecting cells than a 10-week interval
- while antibody levels dipped after the first dose, levels of T-cells – a different type of immune cell – remained high
- the longer schedule led to fewer T-cells overall but a higher proportion of a specific type or subset, called helper T-cells, which according to the researchers, supports immune memory.
Prof Susanna Dunachie, the joint chief investigator in the Pitch study, at Oxford University, said two doses were better than one but the timing of the second was somewhat flexible depending on the circumstances.
I wish to apologize to everyone to whom I vented my unfounded opinion.
Editor’s note: What we are seeing here, is science in action. While the WHO has not yet updated its advice to countries using the Pfizer two dose vaccine, other countries – like South Africa – have decided to follow the advice of this study. This is the nature of science in that it is self correcting as more evidence comes to light. Here at davepepler.com, we will strive to bring you the same facts. If we were wrong, we will correct it and bring you the latest facts.
