Comparison of Natural and BNT162b2 Vaccine-induced Immunity, with and without an Enhancer or Booster Dose, on the Risk of COVID-19-Related Hospitalization in Israel

Introduction: With the COVID-19 pandemic ongoing, accurate assessment of population immunity and the effectiveness of booster and enhancer vaccines is critical. Methods We compare COVID-19-related hospitalization incidence rate ratios, adjusted for potential demographic, clinical and health-seeking-behavior confounders, in 2,412,755 individuals (235,552,274 person-days), across four exposures: 2 BNT162b2 doses, 5 or more months prior ("non-recent vaccine immunity"); 3 BNT162b2 doses (“boosted vaccine immunity”); previous COVID-19, with or without a subsequent BNT162b2 dose (“natural immunity” and “enhanced natural immunity” respectively). Results Compared with non-recent vaccine immunity, COVID-19-related hospitalization incidence rate ratios are 11% (9%-13%) for boosted vaccine immunity, 34% (23%-50%) for natural immunity and 25% (17%-39%) for enhanced natural immunity. Conclusion We demonstrate that natural immunity (enhanced or not) provides better protection against COVID-19-related hospitalization than non-recent vaccine immunity, but less protection than that attained from booster vaccination. Additionally, our results suggest that vaccinating individuals with natural immunity further enhances their protection.

Persistence of vaccine immunity against canine parvovirus and canine distemper virus for determination of vaccine protocol in dogs: impacts and challenges in Brazil

Vaccine protocols were established for dogs and cats, considering the circulating period of maternal antibodies from the puppies, the type of antigen used to make the vaccines and the vaccine immunity duration. This study aimed to approach the duration of vaccine immunity against the canine parvovirus (CPV-2) and the canine distemper virus (CDV), as determining factor to choose the adequate vaccine protocol, besides to stand out the main implications found in Brazil that difficult the application of these current protocols, as the technical challenges to use them. For that, this article described some information about the types of current vaccines, the immunity duration against the CPV-2 and CDV, as well the respective vaccine protocols that were applied. The searches were done in the database of PubMed, SciELO, Google Scholar, Capes Journals and academic books, by the following keywords: vaccination guidelines; humoral immune response; vaccination strategy; distemper; parvovirus infection; and duration of vaccine immunity. Considering the facts, it is understood that the annual revaccination against the CPV-2 and CDV for dogs must be individually assessed, because the vaccine immunity has an average duration of three years, that is, the best alternative for the animal would be the application of routine serological tests, aiming to assess if the antibodies titration remains protective. Another alternative is the use of divalent or trivalent vaccines.

Genotyping of Porcine Circovirus 2 (PCV-2) in Vaccinated Pigs Suffering from PCV-2-Systemic Disease between 2009 and 2020 in Spain

Vaccination against porcine circovirus 2 (PCV-2) is a common practice all over the world. Vaccines can prevent PCV-2-systemic disease (PCV-2-SD) outbreaks but not PCV-2 infection, which can be detectable in a percentage of vaccinated animals. Occasionally, PCV-2-SD is diagnosed in vaccinated farms. The objective of this study was to genotype the PCV-2 strains detected in vaccinated animals diagnosed with PCV-2-SD. Additionally, the evolution of the frequency of PCV-2 genotype detection at Spanish, European, and world levels was assessed. Fifty cases diagnosed as PCV-2-SD between 2009 and 2020 were included in this study. PCV-2 genotype was determined by sequencing the Cap gene region. Among them, only PCV-2b (23/50, 46%) and PCV-2d (27/50, 54%) genotypes were detected. Although the frequency of detection of these two genotypes was similar, their temporal distribution was different. Whereas most PCV-2b sequences (17/23, 74%) were detected between 2009 and 2012, PCV-2d sequences were obtained from 2013 to 2020. Indeed, a predominance of the PCV-2d genotype was observed from 2013 onwards, a trend also noticed at European and world levels. The results suggest that detection of particular genotypes in vaccinated animals probably reflects the general prevalence of the genotypes over time rather than genotype-specific vaccine-immunity escaping.