An Israeli study has concluded that the short-lived immunity and rapid waning of the Pfizer BioNTech COVID-19 vaccine necessitates the reevaluation of future COVID-19 vaccination campaigns. The authors said that while the vaccine was effective in decreasing morbidity and mortality, “its relatively small effect on transmissibility of Omicron … and its rapid waning call for reassessment of future booster campaigns.”
The peer-reviewed paper was published on Nov. 7 in Nature Communications. The retrospective analysis examined the waning effect of protection from the vaccine, which the authors said had not been thoroughly analyzed before in terms of cycle threshold and infectivity. The cycle threshold value stands for the number of cycles it takes a polymerase chain reaction (PCR) test to detect a virus.
PCR testing was a widely used test during the pandemic to determine if people had caught SARS-CoV-2, the coronavirus that causes the COVID-19 disease.
Cycle threshold negatively correlates with viral load which is a major factor of infectivity. So a higher cycle threshold value reflects lower infectivity. The study compared cycle threshold levels of individuals that were unvaccinated, vaccinated with two, three, or four doses, with individuals who had recovered from COVID-19 and had not been vaccinated.