As the Swedish government is preparing booster COVID shots for swaths of the population, including risks groups, vaccine researcher Matti Sällberg, a professor and biomedical analyst at the Karolinska Institute, has ventured that further doses may become necessary.
"We don't know how long the vaccine protects against serious illness and death. This means that you pick the safe before the unsafe", Sällberg told the newspaper Aftonbladet.
According to Sällberg, the Swedish Public Health Agency's announcement of third doses, already this autumn for risk groups, including the elderly and those with compromised immune systems, did not come as a surprise.
"It was highly expected. On the one hand, we know that the virus will not disappear, and the Swedish Public Health Agency has already flagged a third dose for risk groups", Matti Sällberg said, calling the preparations "extremely reasonable".
"After receiving the second dose, the immune response slowly subsides. Within a year, many may have lost their protection. We do not know yet, but if you get a third dose, it will be activated again", he mused. "Biology says that a fading immune response is not unlikely. Then it's time for a third, fourth, maybe fifth dose".
Per Sällberg, "it is not at all unlikely that we might end up in a situation where you have to give recurring shots".
Currently, there are only very limited studies on the effect of a booster dose. But existing studies still indicate a stronger immune response, according to Sällberg, with no indication of an increased risk of side effects.
"On the contrary. Studies on the AstraZeneca vaccine showed that the risk of blood clots was greater in the first dose. So whoever got a dose and everything went well has no reason to worry", Matti Sällberg said.
Matti Sällberg is the founder and the chairman the board at the vaccine company Svenska Vaccinfabriken (SVF).
At present, it is remains unclear how large the refill dose will be and when it will be administered. This depends, among other things, on new virus strains and vaccine protection over time, the Swedish Public Health Agency said in a press release.
"The assessment is that it is not possible to eradicate the virus, and therefore vaccination work should be long-term and focused on reducing serious illness and death", state epidemiologist Anders Tegnell said.
To date, Sweden has seen 1.1 million cases, with 14,700 deaths, more than its Scandinavian cousins combined. So far, it has managed to vaccinate 42.5 percent of its 10 million population.