In the study, the scientists said that their shot was 67% effective in protecting people from COVID-19 disease, and nearly 100% effective in shielding them from severe disease requiring hospitalization.
They also took weekly swabs from the study volunteers and tested them for the COVID-19 virus, and found 50% fewer positive tests among people who were vaccinated than among people who weren’t.
Because people who don’t test positive are less likely to be infected, and therefore unable to spread the virus, they extrapolated from that data that their shot can lower spread of the virus.
Public health officials say the findings still need to be confirmed. It is true that people who were vaccinated had less virus in them if they were infected, but one cannot conclude that they don’t spread the virus to others. As infectious disease experts like to say, all it takes is one virus to cause an infection.
“The fact is that what they showed is that there was decreased viral shedding, or decreased detection of the virus,” says Dr. Carlos del Rio, an infectious disease expert and executive associate dean at Emory University. That doesn’t mean, he says, that the virus isn’t still there and can’t be transmitted to another person.
It remains unclear whether getting vaccinated can stop you from spreading the virus if you’re infected. Definitive studies to confirm that haven’t been completed yet.
Follow the recommendation that even if you have gotten both shots: wear a mask, practice social distancing, and avoid crowded areas, especially indoors.
Everyone is pandemic weary, but if these practices continue to be followed, it will be harder for the virus to continue spreading.