1. We @ImmunologyTang @ShanLuLiu1 are very happy to see our work finally published. We found that current mRNA vaccines induced relatively suboptimal respiratory mucosal immunity despite strong circulating humoral and cellular immunity being induced.
2. Most prior studies focused on blood immune responses induced by vaccination or infection, but the mucosal immunity elicited is largely uncharacterized in the respiratory tract. Here we compared lung and blood humoral and cellular immunity following vaccination and infection.
3.We found that vaccination elicited weak mucosal IgA and neutralizing Ab, particularly against Omicron. Also current vaccines failed to induce significant mucosal T and B cell memory despite marked T/B memory in the circulation.
4. Thus, despite the induction of robust circulating immunity, mRNA vaccines likely do not provoke sufficient mucosal immunity that would be needed for the immediate clearance of the infectious virus to prevent the establishment of infection by SARS-CoV-2 VOCs like Omicron.
5.We suggest mucosal humoral immunity is particularly vulnerable for immune escape. It is thus likely that the current vaccine strategy, even with further boosters, will not achieve “herd immunity” or prevent the occurrence of new infections with future VOCs.
