Whereas recurrent tonsillitis is characterised by apoptotic death of lymphoid tissue, tonsillar hypertrophy is caused by environmental pollution agents that trigger the chronic inflammatory process without apoptotic cell death.

mRNA-based vaccines effectively induce protective neutralizing antibodies against SARS-CoV-2, the etiological agent of COVID-19. Yet, the kinetics and compositional patterns of vaccine-induced antibody responses to the original strain and emerging variants of concern remain largely unknown. Here we characterized serum antibody classes and subclasses targeting the spike receptor-binding domain of SARS-CoV-2 wild type and α, β, γ and δ variants in a longitudinal cohort of SARS-CoV-2 naïve and COVID-19 recovered individuals receiving the mRNA-1273 vaccine. We found that mRNA-1273 vaccine recipients developed a SARS-CoV-2-specific antibody response with a subclass profile comparable to that induced by natural infection. Importantly, these antibody responses targeted both wild type SARS-CoV-2 as well as its α, β, γ and δ variants. Following primary vaccination, individuals with pre-existing immunity showed higher induction of all antibodies but IgG3 compared to SARS-CoV-2-naïve subjects. Unlike naïve individuals, COVID-19 recovered subjects did not mount a recall antibody response upon the second vaccine dose. In these individuals, secondary immunization resulted in a slight reduction of IgG1 against the receptor-binding domain of β and γ variants. Despite the lack of recall humoral response, vaccinees with pre-existing immunity still showed higher titers of IgG1 and IgA to all variants analyzed compared to fully vaccinated naïve individuals. Our findings indicate that mRNA-1273 vaccine triggered cross-variant antibody responses with distinct profiles in vaccinees with or without pre-existing immunity and suggest that individuals with prior history of SARS-CoV-2 infection may not benefit from the second mRNA vaccine dose with the current standard regimen.

would have been low. Additionally, viral interference, with SARS-CoV-2 being the dominant respiratory pathogen, might have contributed to the decrease in rates of other respiratory viral illnesses. This idea is not unfounded. During the H1N1 pandemic in 2009, while the number of H1N1 influenza cases increased, the incidence of seasonal influenza and RSV decreased significantly compared to prior years. This trend lasted until the H1N1 strain transitioned from a pandemic to a seasonal virus the following year. 9 In conclusion, SARS-CoV-2 was the dominant pathogen, while other community respiratory viral and group A Streptococcus throat infections markedly declined in frequency in both adults and children during the 2020-2021 season compared to 2019-2020. The reason for the decline may be attributed to the mitigating measures widely employed in the community. Although it is difficult to predict the incidence of respiratory viral infections after the resolution of the COVID-19 pandemic, it is likely that the number of non-SARS-CoV-2 respiratory infections will rise back to normal in the coming years as SARS-CoV-2 becomes a seasonal virus.

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