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The Omicron variant of SARS-CoV-2 is now globally dominant but despite high prevalence little is known regarding the immune response in children. We determined the antibody and cellular immune response following Omicron infection in children aged 6-14 years and related this to prior SARS-CoV-2 infection and vaccination status. Primary Omicron infection elicited a weak antibody response and only 53% of children developed detectable neutralising antibodies. In contrast, children with secondary Omicron infection following prior infection with a pre-Omicron variant developed 24-fold higher antibody titres and neutralisation of Omicron. Vaccination elicited the highest levels of antibody response and was also strongly immunogenic following prior natural infection with Omicron. Cellular responses against Omicron were robust and broadly equivalent in all study groups. These data reveal that primary Omicron infection elicits a weak humoral immune response in children and may presage a clinical profile of recurrent infection as seen with antecedent seasonal coronaviruses. Vaccination may represent the most effective approach to control infection whilst cellular immunity should offer strong clinical protection.
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ObjectivesTo assess the relative immunogenicity of standard or extended interval BNT162b2 vaccination. DesignPopulation based cohort study comparing immune responses 2 weeks after the second vaccine, with appropriate time-matched samples in participants who received standard or extended interval double vaccination. SettingPrimary care networks, Birmingham, UK. December 2020 to April 2021. Participants172 people aged over 80 years of age. All donors received the BNT162b2 Pfizer/BioNTech vaccination and were vaccinated with either a standard 3 week interval between doses or an extended interval schedule. Main outcome measuresPeak quantitative spike-specific antibody and cellular immune responses. ResultsIn donors without evidence of previous infection the peak antibody response was 3.5-fold higher in donors who had undergone delayed interval vaccination. Cellular immune responses were 3.6-fold lower. ConclusionPeak antibody responses after the second BNT162b2 vaccine are markedly enhanced in older people when this is delayed to 12 weeks although cellular responses are lower. Extended interval vaccination may therefore offer the potential to enhance and extend humoral immunity. Further follow up is now required to assess long term immunity and clinical protection. What is already known on this topicThe BNT162b2 vaccine is highly effective against Covid-19 infection and was delivered with a 3-week time interval in registration studies. However, this interval has been extended in many countries in order to extend population coverage with a single vaccine. It is not known how immune responses after the second dose are influenced by delaying the second vaccine. What this study addsWe provide the first assessment of immune responses in the first 14 weeks after standard or extended interval BNT162b2 vaccination and show that delaying the second dose acts to strongly boost the peak antibody response in older people. The extended interval vaccination may offer a longer period of clinical protection. This information will be of value in optimizing vaccine regimens and help guide guide vaccination policies.
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OBJECTIVES@#The incidence of multimorbidity (MM) and its correlates among older adults remain poorly understood. This study aimed to examine the socio-demographic and lifestyle factors associated with MM in New Zealand. @*METHODS@#People aged 55-70 years were invited to participate in a population-based cohort study, the Health Work and Retirement Study, in 2006. Those who accepted the invitation and completed the baseline questionnaire were followed up on a biennial basis. Data on socio-demographic factors, health and lifestyle behaviours, and diagnoses of chronic diseases were obtained from baseline and 6 waves of follow-up. Generalised estimating equations (GEE) adjusted for both time-constant and time-varying factors were used to model factors associated with the onset of MM. @*RESULTS@#A total of 1,673 participants (with 0 or 1 chronic condition) contributed to an overall 8,616 person-years of observation. There were 590 new cases of MM over 10 years of follow-up, corresponding to an overall incidence of 68.5 per 1,000 person-years. The results of the age- and sex-adjusted GEE analysis showed that age, ethnicity, living alone, obesity, hypertension, and having 1 chronic condition at baseline were significant predictors of MM onset. Higher education, income, physical activity, and regular alcohol consumption were protective factors. In a fully adjusted model, marital status (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.01 to 1.37; p=0.039), hypertension (OR, 1.23; 95% CI, 1.02 to 1.48; p=0.032) and having 1 chronic condition at baseline (OR, 2.92; 95% CI, 2.33 to 3.67; p<0.001) remained significant. @*CONCLUSIONS@#The higher incidence of MM among Māori people, socioeconomically disadvantaged groups, those with low physical activity, and obese individuals highlights the importance of targeted prevention strategies.
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OBJECTIVES@#The incidence of multimorbidity (MM) and its correlates among older adults remain poorly understood. This study aimed to examine the socio-demographic and lifestyle factors associated with MM in New Zealand. @*METHODS@#People aged 55-70 years were invited to participate in a population-based cohort study, the Health Work and Retirement Study, in 2006. Those who accepted the invitation and completed the baseline questionnaire were followed up on a biennial basis. Data on socio-demographic factors, health and lifestyle behaviours, and diagnoses of chronic diseases were obtained from baseline and 6 waves of follow-up. Generalised estimating equations (GEE) adjusted for both time-constant and time-varying factors were used to model factors associated with the onset of MM. @*RESULTS@#A total of 1,673 participants (with 0 or 1 chronic condition) contributed to an overall 8,616 person-years of observation. There were 590 new cases of MM over 10 years of follow-up, corresponding to an overall incidence of 68.5 per 1,000 person-years. The results of the age- and sex-adjusted GEE analysis showed that age, ethnicity, living alone, obesity, hypertension, and having 1 chronic condition at baseline were significant predictors of MM onset. Higher education, income, physical activity, and regular alcohol consumption were protective factors. In a fully adjusted model, marital status (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.01 to 1.37; p=0.039), hypertension (OR, 1.23; 95% CI, 1.02 to 1.48; p=0.032) and having 1 chronic condition at baseline (OR, 2.92; 95% CI, 2.33 to 3.67; p<0.001) remained significant. @*CONCLUSIONS@#The higher incidence of MM among Māori people, socioeconomically disadvantaged groups, those with low physical activity, and obese individuals highlights the importance of targeted prevention strategies.
