Sterilizing Immunity against COVID-19: Developing Helper T cells I and II activating vaccines is imperative

Abstract

Six months after the publication of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) sequence, a record number of vaccine candidates were listed, and quite a number of them have since been approved for emergency use against the novel coronavirus disease 2019 (COVID-19). This unprecedented pharmaceutical feat did not only show commitment, creativity and collaboration of the scientific community, but also provided a swift solution that prevented global healthcare system breakdown. Notwithstanding, the available data show that most of the approved COVID-19 vaccines protect only a proportion of recipients against severe disease but do not prevent clinical manifestation of COVID-19. There is therefore the need to probe further to establish whether these vaccines can induce sterilizing immunity, otherwise, COVID-19 vaccination would have to become a regular phenomenon. The emergence of SARS-CoV-2 variants could further affect the capability of the available COVID-19 vaccines to prevent infection and protect recipients from a severe form of the disease. These notwithstanding, data about which vaccine(s), if any, can confer sterilizing immunity are unavailable. Here, we discuss the immune responses to viral infection with emphasis on COVID-19, and the specific adaptive immune response to SARS-CoV-2 and how it can be harnessed to develop COVID-19 vaccines capable of conferring sterilizing immunity. We further propose factors that could be considered in the development of COVID-19 vaccines capable of stimulating sterilizing immunity. Also, an old, but effective vaccine development technology that can be applied in the development of COVID-19 vaccines with sterilizing immunity potential is reviewed.

Long- and short-term effects of cross-immunity in epidemic dynamics

“…Hopes of herd immunity against SARS-CoV-2 often faltered as it became evident that vaccines would not be sterilizing [7]. Following the same logic, several research strategies bet on sterilizing vaccines as a more definitive way out of this and other pandemics [31–35]. Our results show that attenuating immunity also modify SIR thresholds substantially.…”

Antimicrobial Resistance in the COVID-19 Landscape: Is There an Opportunity for Anti-Infective Antibodies and Antimicrobial Peptides?

“…In contrast, vaccines that cause "non-sterile" immunity protect the host from the disease but do not stop the disease from spreading. prevent the emergence of new variants and reduce the development of resistance, it is essential that the virus cannot replicate among infected people, so vaccines that provide sterilizing immunity or measures that prevent the colonization of the virus in tissues are desirable (54,55). The administration of COVID-19 vaccination, and other vaccines for simultaneous co-infections, are anticipated as a safe and effective measure to prevent infections (56) and further evolution of variants (57).…”

Effectiveness of Covid-19 vaccines against SARS-CoV-2 Omicron variant (B.1.1.529): A systematic review with meta-analysis and meta-regression

“…Meanwhile, neutralizing antibodies can provide sterilizing immunity to prevent infection. [45][46][47] Neutralizing antibodies produced by plasma B cells decay over time, but long-lived plasma B memory cells continuously secrete neutralizing antibodies even after the infection ends, maintaining their level. 48 Moreover, a robust immune response and multiple infections or vaccination can elicit strong immunoglobulin G (IgG)-binding affinity as a result of an affinity maturation process.…”