The role of vaccines in the COVID-19 pandemic: what have we learned?

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged late in 2019 and caused the coronavirus disease 2019 (COVID-19) pandemic that has so far claimed approximately 20 million lives. Vaccines were developed quickly, became available in the end of 2020, and had a tremendous impact on protection from SARS-CoV-2 mortality but with emerging variants the impact on morbidity was diminished. Here I review what we learned from COVID-19 from a vaccinologist’s perspective.

Protective effect and molecular mechanisms of human non-neutralizing cross-reactive spike antibodies elicited by SARS-CoV-2 mRNA vaccination

“…Grids were imaged on a Titan Krios microscope operated at 300 kV and equipped with a Gatan K3 Summit direct detector. 5,894 movies were collected in counting mode at a total dose of 52.51 e - /Å 2 at a magnification of 81,000, corresponding to a calibrated pixel size of 1.069 Å. Defocus values were from −0.5 to −1.5 μm.…”

RBD-Adjuvanted Preparation: Evaluation of IgG and IgM Antibodies for One Year and Cross-Reactivity with Omicron Variant in Mice

“…Despite the reduction in the number of cases and deaths at the present (2023), new waves could emerge at any time, considering the emergence of new variants that may not be controlled by the immune system [1,2]. Even now, several candidate vaccines are still being developed, in an attempt to meet new COVID-19 challenges: since the majority of the population was vaccinated, new vaccines will act as boosters; there is a lack of vaccine for specific populations, as newborns; and long-lasting response has not been achieved with current vaccines [2][3][4].…”

“…The development of neutralizing antibodies against COVID-19 has been considered an established correlate of protection [1,4]. Clinical and epidemiological studies support that prior exposure to SARS-CoV-2 by infection and/or vaccination is likely to attenuate the severity of subsequent infections [1].…”

“…Clinical and epidemiological studies support that prior exposure to SARS-CoV-2 by infection and/or vaccination is likely to attenuate the severity of subsequent infections [1]. Therefore, we must emphasize the importance of cross-reactive protection, considering the emergence of highly transmissible variants, such as Omicron [2,4] It is relevant to study the presence of an immune response against SARS-CoV-2 during pregnancy and maternal-fetal transmission of antibodies, in order to protect newborns [5]. That is highly important considering the suceptibility of infants to COVID-19 and, although most pediatric cases are mild, children still should be protected [6].…”

“…The first part of this study, published previously [19], showed that the same adjuvant contributed to the functionality of the humoral response and led to passive transfer of antibodies to the offspring. We used recombinant Receptor binding domain (RBD), due to its high immunogenicity and potential to induce neutralizing antibodies [4], associated with the following adjuvants mixtures: dimethyldioctadecylammonium bromide and saponin (DDA/Sap) or Outer membrane vesicles and aluminum hydroxide (OMV/AH). We already published the results concerning IgG response and its functionality by avidity and neutralization against Wuhan strain [19].…”