1. Thompson MG, Burgess JL, Naleway AL, et al. Prevention and attenuation of COVID-19 with the BNT162b2 and mRNA-1273 vaccines. N Engl J Med 2021;385:320–329.

2. Tang L, Hijano DR, Gaur AH, et al. Asymptomatic and symptomatic SARS-CoV-2 infections after BNT162b2 vaccination in a routinely screened workforce. JAMA 2021;325:2500–2502.

4. Xin H, Li Y, Wu P, et al. Estimating the latent period of coronavirus disease 2019 (COVID-19). Clin Infect Dis 2022;74:1678–1681.

5. Orenstein W, Offit P, Edwards KM, Plotkin SA. Plotkin’s Vaccines. 7th ed. Philadelphia (PA): Elsevier, 2017. 6. Kim JY, Bae S, Park S, et al. Comparison of antibody and T cell responses induced by single doses of ChAdOx1 nCoV-19 and BNT162b2 vaccines. Immune Netw 2021;21:e29.

7. Kim JY, Lim SY, Park S, et al. Immune responses to the Ch-AdOx1 nCoV-19 and BNT162b2 vaccines and to natural coronavirus disease 2019 infections over a 3-month period. J Infect Dis 2022;225:777–784.

8. Feng S, Phillips DJ, White T, et al. Correlates of protection against symptomatic and asymptomatic SARS-CoV-2 infection. Nat Med 2021;27:2032–2040.

9. Inoue T, Moran I, Shinnakasu R, Phan TG, Kurosaki T. Generation of memory B cells and their reactivation. Immunol Rev 2018;283:138–149.

10. Levin EG, Lustig Y, Cohen C, et al. Waning immune humoral response to BNT162b2 COVID-19 vaccine over 6 months. N Engl J Med 2021;385:e84.

11. Shrotri M, Navaratnam AM, Nguyen V, et al. Spike-antibody waning after second dose of BNT162b2 or ChAdOx1. Lancet 2021;398:385–387.

12. Purtha WE, Tedder TF, Johnson S, Bhattacharya D, Diamond MS. Memory B cells, but not long-lived plasma cells, possess antigen specificities for viral escape mutants. J Exp Med 2011;208:2599–2606.

13. Khurana S, Coyle EM, Dimitrova M, et al. Heterologous primeboost vaccination with MF59-adjuvanted H5 vaccines promotes antibody affinity maturation towards the hemagglutinin HA1 domain and broad H5N1 cross-clade neutralization. PLoS One 2014;9:e95496.

14. Ochsenbein AF, Pinschewer DD, Sierro S, Horvath E, Hengartner H, Zinkernagel RM. Protective long-term antibody memory by antigen-driven and T help-dependent differentiation of long-lived memory B cells to short-lived plasma cells independent of secondary lymphoid organs. Proc Natl Acad Sci U S A 2000;97:13263–13268.

15. Aiba Y, Kometani K, Hamadate M, et al. Preferential localization of IgG memory B cells adjacent to contracted germinal centers. Proc Natl Acad Sci U S A 2010;107:12192–12197.

16. Song JS, Lee J, Kim M, et al. Serial intervals and household transmission of SARS-CoV-2 Omicron variant, South Korea, 2021. Emerg Infect Dis 2022;28:756–759.

17. Abbott S, Sherratt K, Gerstung M, Funk S. Estimation of the test to test distribution as a proxy for generation interval distribution for the Omicron variant in England. medRxiv 2022;Jan. 8. [Preprint]. https://doi.org/10.1101/2022.01.08.22268920 .