- New research finds that COVID-19 mRNA vaccines provide immunity for at least 6 months.
- But because COVID-19 is so new, experts don’t know if immunity will decrease after that.
- Experts say more research will be needed to understand whether people will need reinforcements regularly for COVID-19.
COVID-19 vaccines produced by Pfizer and Moderna are highly effective in preventing cases of COVID-19 in real-world conditions, and research suggests that they should be maintained over time.
What is still unclear, however, is exactly how long COVID-19 vaccines prevent, whether booster shots can be made on the road, or whether vaccines will need to be modified to fight emerging variants of the virus.
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They found that messenger RNA (mRNA) vaccines developed by pharmaceutical companies Pfizer-BioNTech and Moderna prevented 80% of cases after the first dose and 90% after the second dose.
The front-line workers in the study tested COVID-19 every week for 13 weeks.
The researchers said the lack of positive COVID-19 testing in the study group indicates that vaccines reduce the risk of transmitting SARS-CoV-2 by vaccinated people to other people.
“Reducing the risk of communicable infection, which can occur between people with asymptomatic infection or between people several days before the onset of symptoms, is especially important among health care workers, lifeguards and other essential and first-time workers. line, given its potential to transmit the virus through close contact with patients and the public, ”the report notes.
“There is growing evidence that … the transmission of the virus after vaccination is very low,” Dr. Susan Bailey, an allergist and immunologist and president of the American Medical Association, told Healthline.
Separately, Pfizer-BioNTech said the phase 3 clinical trial of its mRNA vaccine shows that strong vaccination persists for at least 6 months among vaccinated individuals.
The researchers found that the vaccine was 100% effective against serious diseases, as defined by the CDC, and 95.3% effective against severe COVID-19, as defined by the Food and Drug Administration (FDA). ).
The vaccine was also found to be 100% effective against one of the major variants of COVID-19 (known as B.1.351) currently circulating in South Africa.
A study that included 12,000 vaccinated people also found “no safety issues” with the Pfizer-BioNTech vaccine, the companies announced.
“The good news is that in the 6-month report on Pfizer’s status, immunity remains very strong and we anticipate that it will continue to be strong,” Bailey said.
“These people [in the study] I’ve had the vaccine longer and he tells us it lasts at least 6 months, ”Bailey added.“ But it’s definitely longer than that, but it won’t just stop happening after 6 months. I would have been worried if efficiency had dropped by a third or half. ”
The fact that the efficacy of the COVID-19 vaccine remains almost unchanged during the study period is an indication that protection will be lasting.
Bailey noted that some vaccines, such as measles, mumps, and rubella, generally confer lifelong immunity. Others, such as the flu vaccine, require a new vaccine each year.
“We don’t know in which field the COVID-19 vaccine will fall,” he said. “If we need a booster shot for COVID-19, we know it will be easy to produce” thanks to new mRNA technology, he added.
Bailey said the vaccines being used now appear to be effective against COVID-19 variants circulating in the United States. But as the coronavirus continues to mutate, more resistant variants could emerge.
“My prediction is that a situation where we should have a booster shot in the future is not because the first dose of vaccine has faded, but because there is a new variant that could emerge,” he said.
As noted in the research, vaccines do not completely eliminate the risk of developing COVID-19.
A recent report on 100 cases of COVID-19 that occurred in vaccinated people in Washington state caused some public alarm.
But experts say such “advanced” cases are expected to account for just a fraction of the more than one million Washington residents who have been vaccinated.
“Finding evidence of advanced vaccine cases reminds us that even if you have been vaccinated, you should still wear a mask, practice social distancing, and wash your hands to prevent the spread of COVID-19 to others who have not. been vaccinated, “he said. Dr. Umair A. Shah, Washington state secretary of health.