So-called “breakthrough” coronavirus cases — infections that occur in people who have been vaccinated against COVID-19 — are rare but can happen, according to a pair of studies published in the New England Journal of Medicine on Tuesday.
The first study focused on frontline workers with the University of Texas Southwestern Medical Center in Dallas. Out of the 8,121 fully vaccinated employees there, only four became infected with the novel virus.
The researchers noted that vaccination had a “dramatic” effect on the medical center’s workforce, noting that they observed a “greater than 90% decrease in the number of employees who are either in isolation or quarantine.”
“Real-world experience with SARS-CoV-2 vaccination at UTSW has shown a marked reduction in the incidence of infections among employees. This decrease has preserved the workforce when it was most needed,” they added.
The second study was based on data of vaccinated workers across several Los Angeles-area hospitals. In that study, only seven of the 14,990 vaccinated health care workers tested positive for COVID-19.
“The rarity of positive test results 14 days after administration of the second dose of vaccine is encouraging and suggests that the efficacy of these vaccines is maintained outside the trial setting,” the researchers wrote. “These data underscore the critical importance of continued public health mitigation measures (masking, physical distancing, daily symptom screening, and regular testing), even in environments with a high incidence of vaccination, until herd immunity is reached at large.”
In both studies, those who did test positive for the novel virus following vaccination had only mild symptoms or were asymptomatic, Francesca Torriani, the lead researcher on the second study, told the New York Times.
Speaking to Fox News, Dr. John Whyte, the chief medical officer for the health care website WebMD, echoed the study authors, noting how becoming fully vaccinated does not equate to a “get out of jail free card” — for now, at least. Though the vaccines are very effective, the studies serve as a reminder that getting the COVID-19 vaccine does not make one completely invulnerable.
“It’s good to remind people what the vaccine efficacy data means. It doesn’t [mean] 95% or 72% of people who get the COVID vaccine won’t get COVID,” he said, referring to efficacy data from the Pfizer-BioNTech and Moderna jabs, as well as the Johnson & Johnson one. “It means that the percentage of persons if exposed to the virus won’t get symptoms. The remaining 5% or 18% will get symptomatic — possibly moderate-severe — if exposed to COVID. So vaccination is not a get-out-of-jail-free card.”
“Until we have a much higher percentage of people vaccinated, you still have to exercise caution. Yes, you can socialize with a small group of people who also have been vaccinated or are at low risk, but vaccination doesn’t mean you can simply return to your pre-pandemic life because even though the risk is lower, it still exists for now.”