Factors Affecting the Antibody Immunogenicity of Vaccines against SARS-CoV-2: A Focused Review

Abstract

Vaccines are a crucial part of the global anti-pandemic effort against COVID-19. The effects of vaccines, as well as their common influencing factors, are the most important issues that we should focus on at this time. To this end, we review statistics on immunogenicity after vaccination, using neutralizing antibodies as the main reference index. Age, infection history, and virus variants are compared, and vaccination program recommendations are made accordingly. Suggestions are made to address concerns raised by the vaccines’ shortened development cycle, as well as the emergence of immunity escape of viral variants. Finally, a brief description and future prospects are provided based on the principle of the ADE effect and previous experience with similar viruses.

Immunogenic and efficacious SARS-CoV-2 vaccine based on resistin-trimerized spike antigen SmT1 and SLA archaeosome adjuvant

“…Strategies based on RBD could circumvent potential antibody-dependant enhancement (ADE) of disease caused by non-neutralizing Ab as seen with preclinical vaccines against the original SARS-CoV 55 . This may not be relevant to SARS-CoV-2, as numerous vaccine strategies based on the entire spike ectodomain have yet to yield any evidence of ADE 56 .…”

COVID-19 Pneumonia in Vaccinated Population: A Six Clinical and Radiological Case Series

“…However, our patient was older than the cases described by Williams et al [30] and he manifested the first symptoms related to Covid-19 infection three days after the second dose of vaccination, in a not fully protective state. Indeed, the protective effect of the second dose vaccines is usually observed after 14 days of vaccination, as has been reported in the literature [31]. For this reason, case 1 may have been infected by SARS-CoV-2 some days after the vaccination However, COVID-19 pneumonia has been rarely described in fully vaccinated patients and there are no yet ongoing clinical trials in these people categories.…”

“…Therefore, it is important to also consider the serology after the COVID-19 vaccination. Not all people, especially those that are immunocompromised, develop a protective im-mune response after vaccination [31,37,41]. On the other hand, we should also consider that the age-related decline in immunity can reduce the prophylactic efficacy of vaccinations.…”

“…We believe that caution should be preserved because some factors can influence vaccine immunogenicity as age factors and the presence of an immunocompromised state. On the other end, emergent researches also raised the question to consider the possibility of Acute enhancement disease (ADE) in presence of virus variants even if this phenomenon has been not fully demonstrated in the clinical trials [31,46]. Future clinical trials and studies in vitro and animal models should be done to better understand this mechanism.…”

“…These data suggested that is also important to monitor the typical clinical status related to oncologic patients. Indeed, an immunocompromised state and the age-related decline of the immune response can compromise the vaccination efficacy [ 31 , 37 ].…”