nezumi wrote: ↑Wed Dec 01, 2021 8:44 am
The original jabs have done the long-term immunity job already
+1. Cellular immunity is for life, not just for Christmas.
A booster will increase antibody levels which will temporarily solve the waning problem.
If it increases the level of antibodies to a greater extent than jab2 then I suppose antibodies will be waning from a higher point so you
might have detectable levels for longer than previously.
I did see a quote somewhere from an immunologist who reckoned a second booster (i.e. the third jab for the immunocompetent) might lead to an increase in the pool of cells which can recognise variants:
https://www.nature.com/articles/d41586-021-02795-x wrote:A third vaccine dose might allow people who haven't been infected to achieve the benefits of hybrid immunity, says Matthieu Mahévas, an immunologist at the Necker Institute for Sick Children in Paris. His team found that some of the memory B cells from naive vaccine recipients could recognize Beta and Delta, two months after vaccination9. “When you boost this pool, you can clearly imagine you will generate potent neutralizing antibodies against variants,” Mahévas says.
Also:
Ellebedy’s team collected lymph-node samples from mRNA-vaccinated individuals and found signs that some of their memory B cells triggered by the vaccination were gaining mutations, up to 12 weeks after the second dose, that enabled them to recognize diverse coronaviruses [...] Goel, University of Pennsylvania immunologist John Wherry and their colleagues found signs that six months after vaccination, memory B cells from naive individuals were continuing to grow in number and evolve greater capacity to neutralize variants8. Antibody levels fell after vaccination, but these cells should start cranking out antibodies if they encounter SARS-CoV-2 again. “The reality is you have a pool of high-quality memory B cells that are there to protect you if you ever see this antigen again,” Goel says.
And, btw:
Extending the interval between vaccine doses could also mimic aspects of hybrid immunity. In 2021, amid scarce vaccine supplies and a surge in cases, officials in the Canadian province of Quebec recommended a 16-week interval between first and second doses (since reduced to 8 weeks).
A team co-led by Andrés Finzi, a virologist at the University of Montreal, Canada, found that people who received this regimen had SARS-CoV-2 antibody levels similar to those in people with hybrid immunity10. These antibodies could neutralize a swathe of SARS-CoV-2 variants — as well as the virus behind the 2002–04 SARS epidemic. “We are able to bring naive people to almost the same level as previously infected and vaccinated, which is our gold standard,” says Finzi.
And while I'm here I might as well add:
https://www.science.org/doi/10.1126/science.abm0829 wrote:
We found mRNA vaccines generated functional memory B cells that increased from 3-6 months post-vaccination, with the majority of these cells cross-binding the Alpha, Beta, and Delta variants. mRNA vaccination further induced antigen-specific CD4+ and CD8+ T cells, and early CD4+ T cell responses correlated with long-term humoral immunity
https://pubmed.ncbi.nlm.nih.gov/34636722/ wrote:
Focusing on the T cell response, we conducted a longitudinal study of infection-naïve and COVID-19 convalescent donors before vaccination and after their first and second vaccine doses, using a high-parameter CyTOF analysis to phenotype their SARS-CoV-2-specific T cells. Vaccine-elicited spike-specific T cells responded similarly to stimulation by spike epitopes from the ancestral, B.1.1.7 and B.1.351 variant strains, both in terms of cell numbers and phenotypes. In infection-naïve individuals, the second dose boosted the quantity and altered the phenotypic properties of SARS-CoV-2-specific T cells, while in convalescents the second dose changed neither.