Single Vaccine Dose May Protect Individuals Who Have Recovered From COVID-19


The potential for some people to skip the second COVID-19 vaccine dose may make more doses available to others.

New research suggests that people who have recovered from COVID-19 may only need a single dose of the vaccine to boost antibodies, a finding that could increase the availability of COVID-19 vaccines for others.

Investigators working with the University of North Carolina (UNC) Chapel Hill’s COVID Health Care Personnel Study followed 193 health workers who submitted to routine tests for antibodies. Participants had the opportunity to receive a COVID-19 vaccine beginning in December 2020. After a single dose, the antibody response in those who previously had COVID-19 was almost twice as high as those with no signs of previous infection, according to a press release.

“If this immune response is shown to be durable and protective against subsequent infection in future studies, individuals with a history of infection may be able to forgo the second dose of an mRNA-based vaccine,” said first study author Emily Ciccone, a fellow in the Division of Infectious Diseases at the UNC School of Medicine, in the press release.

Corresponding author Allison Aiello, PhD, added that the response to the first vaccination among individuals with prior infection was similar to 2 vaccine doses among those who had never been infected.

The researchers noted that there was a limited number of people with a prior infection in the study group. Despite this small sample size, however, they found a significant difference in response to the first vaccination.

This finding has been corroborated by other recent studies, according to the press release. A strength of the current study is that the investigators were able to measure antibody responses both before and after vaccination, in some cases for months prior to the first vaccine dose, according to the authors.

“These results support a new and growing body of research suggesting that prior coronavirus infection may act as a primer for the immune response to the first dose of mRNA-based COVID-19 vaccine,” Ciccone concluded in the press release.


Single vaccine dose may offer protection to those who have had COVID-19 [news release]. UNC Chapel Hill; March 9, 2021. Accessed March 9, 2021.

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