Breakthrough infections may be less transmissible, study suggests
A new study from the Netherlands concluded that when rare breakthrough COVID-19 infections occur in vaccinated individuals, the viral loads are comparable to those in unvaccinated, infected people. But there's simultaneously less infectious viral particle shedding, which in other words suggests that vaccinated people are probably still less likely to transmit the virus, though further study is necessary.
The non-peer reviewed findings are based on an analysis of 161 breakthrough infections — the majority of which were caused by the Delta variant — among a population of 24,706 vaccinated health-care workers. They seem to line up with some other evidence that indicate a reduced transmission risk among the vaccinated who contract the virus.
While that appears to be good news, the Dutch study does leave some room for concern, since 68 percent of the samples were still found likely to be infectious, a number that the University of Pittsburgh's Walid Gellad thinks is too high for comfort.
The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
A free daily email with the biggest news stories of the day – and the best features from TheWeek.com
Tim is a staff writer at The Week and has contributed to Bedford and Bowery and The New York Transatlantic. He is a graduate of Occidental College and NYU's journalism school. Tim enjoys writing about baseball, Europe, and extinct megafauna. He lives in New York City.
-
The 8 best dark comedies of the 21st centuryFrom Santa Claus to suicide terrorism, these movies skewered big, taboo subjects
-
France’s ‘red hands’ trial highlights alleged Russian disruption operationsUNDER THE RADAR Attacks on religious and cultural institutions around France have authorities worried about Moscow’s effort to sow chaos in one of Europe’s political centers
-
Codeword: October 30, 2025The Week's daily codeword puzzle
-
Covid-19 mRNA vaccines could help fight cancerUnder the radar They boost the immune system
-
FDA OKs generic abortion pill, riling the rightSpeed Read The drug in question is a generic version of mifepristone, used to carry out two-thirds of US abortions
-
The new Stratus Covid strain – and why it’s on the riseThe Explainer ‘No evidence’ new variant is more dangerous or that vaccines won’t work against it, say UK health experts
-
RFK Jr. vaccine panel advises restricting MMRV shotSpeed Read The committee voted to restrict access to a childhood vaccine against chickenpox
-
Texas declares end to measles outbreakSpeed Read The vaccine-preventable disease is still spreading in neighboring states, Mexico and Canada
-
RFK Jr. shuts down mRNA vaccine funding at agencySpeed Read The decision canceled or modified 22 projects, primarily for work on vaccines and therapeutics for respiratory viruses
-
Measles cases surge to 33-year highSpeed Read The infection was declared eliminated from the US in 2000 but has seen a resurgence amid vaccine hesitancy
-
Kennedy's vaccine panel signals skepticism, changeSpeed Read RFK Jr.'s new vaccine advisory board intends to make changes to the decades-old US immunization system
