Can You Get COVID After Getting Vaccinated?
There are reports of people who contracted COVID-19 even though they were vaccinated, such as these four people in Oregon and these 12 in Hawaii . But these are just a few cases out of the millions vaccinated. New research confirms that vaccines are extremely effective under real-world conditions and that such breakthrough cases are rare.
In Phase 3 studies, which were required before vaccines were approved, Moderna was 94% effective against symptomatic infections, while Pfizer was 95% effective . These numbers refer to the effectiveness of the vaccine, a number calculated from laboratory tests. If the number of cases in the group of vaccinated people is 5% more than in the control group, the vaccine is 95% effective. This is an important number to calculate during the test, but it is not the same as actual efficiency .
Likewise, the Johnson & Johnson vaccine was calculated to be 66% effective , although the vaccine trial was conducted in an environment where there were more new variants in circulation, so this number cannot be directly compared with the other two. The experts said that all three vaccines are effective and there is no compelling reason to abandon one vaccine in favor of another .
What about real efficiency?
New research released today provides more information on effectiveness in real life situations. Almost 4,000 people who received the Pfizer or Moderna vaccine in December were followed up for three months; they regularly wiped their noses and sent samples to the CDC for coronavirus testing, whether they got sick or not.
The results were excellent: the people in the study were 90% protected from infection after being fully vaccinated (14 days after the second dose) and 80% during the time period that began 14 days after the first dose.
The volunteers in the study were healthcare workers and other important workers, mostly between the ages of 18 and 49, mostly white, and there were more women than men.
While the Phase 3 trials only tested participants if they had symptoms of COVID, this study tested everyone, so we have new information: Vaccines are effective against infection, not just symptomatic infection. Until recently, we weren’t sure if vaccines stop people from getting the virus or just make them less likely to develop symptoms. This study is one of the first to show that the vaccine prevents asymptomatic infections.
Breakthrough infections are rare
But there were also breakthrough infections. Of the 994 people who were not vaccinated, 161 contracted the infection. Compared to this, the vaccine was very effective, but not perfect. There were eight infections among people who received only one dose of the vaccine, and only three among people who received both doses.
When you see news reports of new infections, it is important to put them in context. If there are so few of them that every handful of cases need to be reported in the news – among the 51 million people who have been fully vaccinated – that in itself is a sign that vaccines are working pretty darn well.
It is also important to note that breakthrough infections may not be as serious as infections in people who have not received the vaccine. Tests have shown that all three vaccines are extremely effective against death and serious illness.
Whether breakthrough infections are easier or not is one of the many open questions about breakthrough infections that researchers are still trying to answer. Others include whether the breakthrough infections in the study could have been caused by new variants of the coronavirus, or whether people with breakthrough infections had something in common (such as pre-existing diseases).