Vaccination, Variants, and Reinfection

Two cases of COVID-19 reinfection occurred in fully vaccinated people with SARS-CoV-2 variants with a number of substitutions. In each of these patients—who had been given the mRNA vaccines—their reinfections showed unique mutations and the investigators speculated they might be of clinical importance.

Findings from the study were published in The New England Journal of Medicine.

The investigators made it clear about the importance to continue the ongoing mass vaccination efforts as well as making the case to support the potential need of a booster in the coming months.

“These observations in no way undermine the importance of the urgent efforts being taken at the federal and state levels to vaccinate the US population," the study authors wrote. "They also lend support to efforts to advance a new vaccine booster (as well as a pan-coronavirus vaccine) to provide increased protection against variants."

The concerns lie in that variants can mutate into viruses with greater transmissibility and mortality. In the United States, the B.1.1.7 has become the dominant strain in the country, and is reported to be more transmissible than the original strain.

“Two areas of concern relate to the ability of variants to evade vaccine-induced immunity and cause asymptomatic infection (and thereby promote viral spread) or illness,” the investigators wrote. “Both consequences are important, both need to be considered independently, and both are largely unknown.”

Patient 1—of the 2 cases—was a 51-year-old woman with no known risk factors and received her first dose of the mRNA-1273 vaccine in January. She received her second dose in February. Nineteen days after the second dose she developed a sore throat, congestion, and headache. She tested positive for COVID-19. The next day she lost her sense of smell and her symptoms resolved in 1 week.

The patient identified as Patient 2 was a 65-year-old woman with no risk factors was given the BNT162b2 vaccine in January. Three weeks later, she received her second dose. In early March, her unvaccinated partner tested positive for SARS-CoV-2. In mid-March, Patient 2 developed fatigue, sinus congestion, and a headache. The next day, which was 36 days after completing her vaccination, she tested positive for CoV-2 RNA. Her symptoms began to resolve in a few days.

Both patients underwent Serial PCR tests of saliva samples before and during their illnesses. Both tested for several mutations, and more detailed analysis of whole-genome sequencing was completed in Patient 1.

Further analysis suggested "Patient 1’s infection resulted from a SARS-CoV-2 variant that is related to but distinct from the known variants of concern (the B.1.1.7 variant first identified in the United Kingdom and the B.1.526 variant first identified in New York City),” investigators wrote.

Ultimately, the investigators say it is a race between SARS-CoV-2 and vaccination, so in the interim period they recommend that the ongoing protection measures remain in place.

“During this critical period, our data support the need to maintain layers of mitigation strategies, including serial testing of asymptomatic persons, open publication and analysis of vaccination and infection databases (such as those accruing data in New York City), and rapid sequencing of SARS-CoV-2 RNA obtained from a variety of high-risk persons,” the investigators concluded.