The researchers behind the ZOE COVID Symptom Study—from King’s College London, Massachusetts General Hospital, Harvard T.H. Chan School of Public Health, and Stanford University School of Medicine—have been tracking COVID patients’ symptoms for more than a year. Lately, they said in a mid-June statement, “We’ve found that sneezing a lot is a more common sign of infection in those who’ve been vaccinated.” RELATED: Half of Unvaccinated People in the U.S. Have This in Common, Research Shows. If you’ve been vaccinated and start sneezing a lot without an explanation, you should definitely get a COVID test, especially if you are living or working around people who are at greater risk from the disease." While incredibly effective—Pfizer and Moderna are about 95 percent effective against symptomatic COVID, while Johnson & Johnson is around 66 percent—the vaccines do not block COVID completely. The researchers say that in general, vaccinated people who do get COVID “experience the same kinds of symptoms as unvaccinated people do, but their illness is milder and shorter”—or they don’t have symptoms at all. However, “sneezing a lot with no explanation after you’ve been vaccinated could be a sign of COVID-19.“ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: The CDC Says 1 in 10 People Who Got Pfizer or Moderna Made This Mistake.