Covid-19 vaccines in use are highly effective at preventing infection and severe cases, and early research suggests they should maintain their effectiveness for at least six months.
What remains unclear, however, is how long the vaccines will maintain that effectiveness and prevent Covid-19, if booster shots or new shots may be needed to improve protection, or if vaccines will need to be changed to fight against new variants.
Bulawayo Provincial Medical Director, Dr Maphios Siamuchembu said the protection length varies with doses.
“The protection length varies with doses. The first dose protects for about two weeks, the second dose about six months, and the booster shots last longer,” said Dr Siamuchembu.
Meanwhile, the Health Desk experts said it is difficult to ascertain since the vaccines have not been in use for very long.
“Some vaccines, such as those for measles, mumps, and rubella, give a person lifetime protection. Others, like the flu vaccine, require a person to get a new shot every year. That’s because, with some shots, immunity can wane. We’re not sure yet which type of vaccine the Covid-19 vaccines will be, but the best estimate is the mRNA vaccines currently in use (the Pfizer-BioNTech and Moderna vaccines) are likely to last for one to three years, and that most vaccines will need to be recurring,” said the Health Desk Experts.
If “booster” shots are needed, or if the Covid-19 vaccines are needed every year, they should be relatively easy to produce—especially mRNA vaccines in use.”
“We don’t know how long vaccines work against Covid-19 yet because they have not been in use for very long. However, Pfizer-BioNTech said that the ongoing phase three trial of its mRNA vaccine shows that strong protection lasts for at least 6 months for individuals who are vaccinated,” said the Experts.
The Experts said estimates on protection could also change if more serious variants are better at infecting vaccinated people.
“The vaccines currently in use have been shown to be effective against most, but not all, Covid-19 variants—particularly those circulating in the United States. But as the virus keeps changing naturally, variants could emerge that the vaccines are less effective against,” they said.
The Experts added that the promising six-month data is an important and helpful milestone nonetheless.
“It tells experts the vaccines are working, and that protection will last longer than six months. Experts estimate that the Pfizer and Moderna vaccines may provide good protection from Covid-19 for one to three years. Manufacturers will continue to monitor the effectiveness of their vaccines,” said the Health Desk Experts.