COVID-19 mRNA Based Vaccine Immune-Response Assessment for Public Health Decision

Background: The Nursing Home Residents (NHR) has been targeted as a vaccination priority due to their higher risk of worse outcome after Covid-19 disease. The mRNA based vaccine BTN2b2 was the first approved in Europe for NHRs. The assessment of the specific vaccine immune response (both humoral and cellular) at long term in NHRs has not been addressed yet.Methods: A representative sample of 624 NHR subjects in North region of Spain was studied to assess immune response against full vaccination with BTN2b2. The anti-S1 antibody levels and specific T cells were measured at 2 and 6 months after vaccination.Results: A 24·4% of NHR had a previous infection prior vaccination. The remaining NHR were included in full vaccination assessment group (FVA). After 2 months, a 94·9% of the FVA presented anti-S1 antibodies whereas those seronegative without specific cellular response were 2·54%. At long-term, the frequency of NHR within the FVA group with anti-S1 antibodies at six months were 86·3% and the seronegative subjects without specific cellular response was 6·11%.Conclusions: The cellular immune assays complement to humoral test in the immune vaccine response assessment. Therefore, the cellular immune assessment in NHRs allows to fine tune those seronegative subjects with potential competent immune response against the vaccine.Funding Information: This work was partially supported by grant from Cantabrian Government #2020 UIC22-PUB-0019.Declaration of Interests: The authors declare no conflict of interest based on ICMJE guidelines.Ethics Approval Statement: The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Regional Ethics Committee (CEIm, internal code 2020.167, 14 May 2020) and with the support of Public Health Service of Cantabrian Governement