Triumphs and tribulations of COVID-19 vaccines: Lessons to be learned from smallpox epidemics in the 1700s

Excerpt

The recent years have been threatened by emerging and re-emerging pathogens, like influenza viruses, Ebola virus, Zika virus, and, currently, SARS-CoV-2, which have rapidly spread globally causing large epidemics with devastating health and economic consequences. These health emergencies dramatically resemble the dreadful epidemics occurring in the pre-antibiotics and pre-vaccine era, like plague and smallpox, whose elimination represented important conquests for humanity. New technologies are allowing the rapid development of effective prophylactic vaccines, the key weapons to defeat the virus, a goal that have been achieved with unprecedented efforts and speed for COVID-19 [1]. As to 10 December 2020, according to World Health Organization landscape documents, 52 COVID-19 candidate vaccines are in clinical evaluation (13 in phase 3 clinical trials) and 162 in preclinical evaluation. Results of phase 1 and 2 clinical trials have been published for inactivated whole virus vaccines, recombinant adenovirus vectored vaccines (rAd5-, rAd26-, and chimpanzee ChAdOx1-vectored vaccines), mRNA vaccines (mRNA-1273 and BNT162b2), and recombinant SARS-CoV-2 spike protein nanoparticle vaccine, which showed the acceptable safety profile and high immunogenicity of all vaccines [1]. …