Abstract: Abstract Not Available
INTRODUCTION
The previous study1 suggested the importance of general precautions against viral infections, such as social distancing, in Japan’s oldest demographic during the early phase of the coronavirus disease 2019 (COVID-19) pandemic without vaccination. As the support of immune potency is essential, boosting the COVID-19 immunity effectively and safely after the primary vaccination may be needed when the immunity wanes or variants expressing new antigens evolve2. To maintain COVID-19 protection, convenience should be also a key element for repetitive booster shots and monitoring their effects.
Considering advanced technologies for vaccination, such convenience could be achieved by nasal or mucosal vaccination with recombinant immunogenic proteins and monitoring saliva immunoglobulins (IgA and IgG) specific to COVID-19. Several clinical trials using intranasal vaccination against COVID-19 have already been undertaken3. Instead of mRNA or virus-vectored vaccination deployed globally, for now, simpler and probably safer vaccines using recombinant Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike proteins may be valuable for boosting the immune potency. The efficacy of the booster can be monitored by saliva IgA and IgG for convenience, which is feasible even at home. It has been demonstrated that IgA and IgG antibodies to SARS-CoV-2 spike antigens in saliva and serum are detected by enzyme-linked immunosorbent assays in COVID-19 patients4. Besides, anti-SARS-CoV-2-specific IgA and IgG antibodies have been demonstrated to secrete into breast milk after COVID-19 vaccination in breastfeeding women5.
During a prolonged COVID-19 pandemic accompanying its mortality and socioeconomic damages, vaccination is one of the important measures to protect people, especially the vulnerable elderly, from the COVID-19 pandemic. After starting the bioengineered novel vaccination, a convenient and safe strategy to maintain the immune potency against COVID-19 and to monitor its efficacy is warranted.
SIGNIFICANCE STATEMENT
This idea will help the researchers to develop a convenient strategy to boost immunity against COVID-19.