Pitfalls in Understanding and Handling of Covid-19 Vaccination ("Any Fool Can Know The Point Is to Understand"1)

The aim of this article is to critically review the managing of vaccination over the course of the present COVID-19 pandemic against the knowledge that had already been at hand and the scientific data that had yet to be learned. In the period before vaccines for COVID-19 became available, the startling similarity in epidemiologic behavior between COVID-19 and the Spanish flu could be observed. The development of vaccines against COVID-19 has evolved at an unprecedented speed resulting in highly im-munogenic vaccines with incredible protective characteristics covering a relatively short follow-up time in clinical trials. The roll-out in the general population turned out to take significantly longer time than the duration of immunity conferred by a 2-dose vaccination schedule (about 3-4 months). Therefore, the SARS-CoV-2 was left with the opportunity for random mutations with each replication cycle, resulting in immune evasion, shortened incubation, shortened serial interval, and increased transmissibility. The short incubation period of COVID-19 requires a steady protective antibody titer to be maintained to avert infection, achieve herd immunity, and terminate the pandemic spread. The protective neutralization titer needed to avert symptomatic infection and infection altogether is about 3% and 20%, respectively, of the mean convalescent titer. The latter corresponds to an absolute titer of 1:10-1:30. The intensity and duration of protective vaccinal and hybrid humoral immunity are explored. From the present perspective, it was naive to believe that a 2-dose vaccination would suffice to counter COVID-19 primarily due to its short incubation and a roll-out that was not catching up with the waning protective vaccinal antibody levels. Besides, the spacing of doses and boosters with respect to previous infection or vaccination, and differences in natural immunity and vaccine-induced immunity (adenovirus-vectored and mRNA) are discussed. The issue of vaccination and multisystem inflammatory syndrome in children is briefly presented. Finally, ethical points are discussed as some vaccine production platforms and neutralization tests use human cell lines derived from aborted fetuses. Conclusion - If the COVID-19 vaccines had been licensed as 3-dose vaccines, with more generous spacing, e.g. 0-2-6 months, providing for quantitatively larger and temporally more durable humoral immunity, that would have enabled attaining a steadier herd immunity and probably a paradoxical earlier effect on stopping the transmission. Copyright © 2022 by the University Clinical Centre Tuzla, Tuzla, Bosnia and Herzegovina.

Summary of New Guidance on Selected Immunizations.

In 2022, the Centers for Disease Control and Prevention (CDC) updated its Adult Immunization Schedule Recommendations for Ages 19 Years or Older to provide the most current evidence-based recommendations following comprehensive reviews of data related to vaccines. In its report, the CDC highlighted the importance of health care professionals staying up to date on the latest evidence. During the novel coronavirus pandemic, the ability to provide routine vaccinations to the adult population was limited and even halted at times. As in-person health care visits continue to resume, it is imperative for nurses to refocus on and be familiar with the most up-to-date vaccine recommendations. Here, we summarize information on vaccine guidelines, safety, and special considerations for women, and we highlight changes to the 2022 adult immunization schedule. Keeping individuals free of vaccine-preventable diseases is one of the most effective and important public health interventions in health care.

Lessons from a mature acellular pertussis vaccination program and strategies to overcome suboptimal vaccine effectiveness.

INTRODUCTION: Despite high vaccination coverage among children and adolescents, pertussis remains a public health problem, with large outbreaks occurring periodically in the US and other developed countries. AREAS COVERED: We examine lessons learned more than 20 years after implementation of programs which use only acellular pertussis vaccines and propose avenues for possible effective use of acellular pertussis vaccine to prevent large outbreaks. EXPERT OPINION: Acellular pertussis vaccines were introduced more than 20 years ago, yet the incidence of pertussis has been increasing over the past decade, with periodic large outbreaks marked by notable shifts in disease burden from infants and young children toward fully vaccinated adolescents and young adults. This age shift is mainly driven by the waning of vaccine immunity. To better protect adolescents against pertussis, modification of the current acellular pertussis vaccination schedule or adoption of new vaccination strategies should be considered. For infants not yet eligible to be vaccinated, maternal vaccination against pertussis during pregnancy is an effective way to protect infants from infection, severe disease and death. Implementation of maternal vaccination programs should be encouraged in countries without one or efforts to improve coverage should be supported in countries with existing program.

Full seroconversion in initial non-responders with higher antibody levels after heterologous COVID-19 vaccination schedule.

Antibody testing after COVID-19 vaccination is generally not recommended. Here, we present the results of a retrospective study, in which we analyzed antibody levels before and after the first dose of the ChAdOx1 vector vaccine. We identified 5% non-responders (43.6 ± 10.6 years; females: 41%) and 3.4% low-responders (44.2 ± 10.1 years; females: 64%) after the first dose. Of these, 61 individuals received a timely second dose either with a homologous (ChAdOx1/ChAdOx1) or heterologous (ChAdOx1/mRNA-1273) schedule. All vaccinees achieved positive S1-specific IgG titers to the ancestral SARS-CoV-2 strain after the second dose, but antibody levels as well as neutralization titers against the ancestral SARS-CoV-2 strain were higher after the heterologous schedule. However, Omicron-specific neutralizing antibodies were not detectable after two doses in either group, indicating that a third vaccine dose is needed to enhance cross-reactive antibodies against currently circulating and emerging variants of concern.