Peer Reviewed

vaccination

COVID-19 Vaccines: Are Boosters Necessary?

Booster doses of the SARS-CoV-2 mRNA vaccines may be necessary for all vaccinated individuals, according to the results of a recent study.1 In addition, a second dose of these vaccines may not be needed in those who have had a prior COVID-19 infection.

The researchers conducted a longitudinal assessment of individuals who were vaccinated against SARS-CoV-2 with either the Pfizer-BioNTech or Moderna mRNA vaccines.2 Included were 28 individuals who had never been previously infected with COVID-19 and 36 participants who had prior infection.

To compare the quantity, quality, and duration of protection between the two groups, the researchers utilized an enzyme-linked immunosorbent assay (ELISA) to measure antibody levels against the SARS-CoV-2 spike protein receptor binding domain (RBD) before, between, and after vaccination doses.

The results indicated that in individuals without prior infection, one vaccine dose provided protection similar to a mild natural infection, while both vaccine doses provided protection similar to a severe natural infection. One vaccine dose in individuals with prior COVID-19 infection resulted in antibody levels similar to that of a severe natural infection. A second dose of the vaccine in those previously infected did not further increase antibody levels.

However, those without prior infection did not develop physiologic neutralizing potency until the second dose of the vaccine while those previously infected demonstrated maximal neutralization after just one dose. Antibody levels in both groups of individuals had a similar lifespan, with an average loss of approximately 90% of antibodies within 90 days.

“In summary, our findings suggest that two doses are important for quantity and quality of humoral immunity in SARS-CoV-2-naïve persons, while a single dose has maximal effects in those with past infection,” the researchers concluded. “Antibodies from vaccination wane with kinetics very similar to that seen after mild natural infection; booster vaccinations will likely be required.”

 

—Leigh Precopio

 

Reference:

  1. Ibarrondo FJ, Hofmann C, Fulcher JA, et al. Primary, recall, and decay kinetics of SARS-CoV-2 vaccine antibody responses. ACS Nano. Published online June 23, 2021. doi: https://doi.org/10.1021/acsnano.1c03972
  2. Had COVID-19? One vaccine dose enough; boosters for all, study says. Press release. Eurekalert. June 23, 2021. Accessed June 23, 2021. https://www.eurekalert.org/pub_releases/2021-06/acs-hco061821.php