If you find any publications talking about that, please link it to us. I saw the recent news story that the Moderna vaccine looses less imunity over time than the Pfizer vaccine. What I read didn't make much sense, and left me scratching my head. Basically, I was surprised that there was such a difference between the two.
I'm really curious about the reported differences between the Pfizer and Moderna vaccines. I had thought they coded for identical spike proteins but perhaps this is not the case?
Of course, another possibility would be an AstraZeneca booster after Pfizer. The second paper mentions "greater CD8+ T cell responses in the ChAd–mRNA group" but I'm not sure if this would result in a real-world improvement against the Delta variant.
Here are a couple articles on the general topic of mixing and matching vaccines. So far I have not seen any reports on mixing Pfizer and Moderna.
>>>Mixing COVID-19 vaccines is emerging as a good way to get people the protection they need when faced with safety concerns and unpredictable supplies. Most vaccines against SARS-CoV-2 must be given in two doses, but multiple studies now back up the idea that mixing the Oxford–AstraZeneca jab and the Pfizer–BioNTech vaccine triggers an immune response similar to — or even stronger than — two doses of either vaccine.
Results
announced on Monday 1 by a UK group suggest that the combination sometimes outperforms two shots of the same vaccine, and a similar picture is emerging from German studies. People can now “feel a bit more comfortable” with the idea of mix-and-match, says immunologist Leif Erik Sander at Charité University Hospital in Berlin. . . . However, the trials so far have been too small to test how effective combinations of vaccines are at preventing people from developing COVID-19. . . . The lingering possibility of rare side effects is one reason some researchers recommend that people stick to the standard two shots of a single vaccine for now. . . . But as new variants of SARS-CoV-2 emerge, the results of mix-and-match trials could provide policymakers with the data they need to switch to more protective combinations. “It’s good to have that data in readiness,” says Fiona Russell, a vaccine researcher at the Murdoch Children’s Research Institute in Melbourne, Australia.<<<
A slew of studies suggests that mixing vaccines provokes potent immune responses, but scientists still want answers on real-world efficacy and rare side effects.
www.nature.com
>>>Similarly, [in a second paper] Schmidt et al. show significantly higher titers of IgG antibodies directed against the SARS-CoV-2 spike protein and receptor-binding domain after ChAd–mRNA (either BNT162b2 or mRNA-1273) or mRNA–mRNA vaccination than after homologous ChAd–ChAd vaccination
3. In addition, the participants dosed with ChAd–mRNA demonstrate a greater number of circulating spike protein–specific CD4+ and CD8+ T cells, as well as cytokine-producing T cells, than that of participants dosed with ChAd–ChAd. Schmidt et al. further demonstrate comparable multifunctional, spike protein–specific CD4+ T cell responses but greater CD8+ T cell responses in the ChAd–mRNA group.<<<
https://www.nature.com/articles/s41591-021-01463-x
Several clinical trials are currently underway for mixing Pfizer’s mRNA shot with AstraZeneca’s viral vector vaccine.
qz.com
