Schematic representation. A total of 110 children received two doses of 10 g monovalent BNT162b2 at day 0 and day 21, and 28 unvaccinated children were naturally infected during a period when Omicron subvariants were dominant in the community. Of the vaccinated children, 34 had immunity conferred only by two doses of vaccine by 6 months (VV). Sixteen children had one dose of vaccine, followed by natural infection, followed by dose two 3 months later, which was given after the 3-month venepuncture (VIV). Sixty children had two doses of vaccine followed by a natural infection either before or after the 3-month venepuncture (VVI). S, symptomatic ( n = 49); A, asymptomatic ( n = 11). Twenty-eight unvaccinated children, who naturally acquired symptomatic SARS-CoV-2 infection, were used for comparison. The immunological parameters at 12 months of the VV children who received a booster but did not acquire infection between 6 and 12 months are displayed as VV + booster ( n = 9).
