What you need to know about a second booster dose to protect against COVID-19

FARGO — Those who are 50 and over are eligible for a second vaccine booster dose to protect against the coronavirus — but is there an ideal time to give the immune system a boost?

“That’s the question that everybody is asking right now,” said Dr. Avish Nagpal, the top infectious disease specialist at Sanford Health. “I don’t know if I have a definitive answer.”

There is currently a lull in COVID-19 infections following the delta wave and explosive omicron wave, which recently subsided.

But a new omicron subvariant is spreading, and experts predict that even if infection rates remain low through spring and summer, another wave could arrive in the fall. Cases are rising in some parts of the country.

A recently published study from Israel found that a second booster dose of the Pfizer vaccine produced antibodies that lasted four or five weeks, then faded.

But the immune system is complex, and while antibodies can prevent infection, other components of the immune system shored up through vaccination help the body prevent a case of COVID-19 from becoming serious enough to result in hospitalization or death, multiple studies have shown.

Those who are 50 and over and considering a second booster should talk to their physician about optimal timing, said Nagpal and Dr. Paul Carson, an infectious disease specialist at North Dakota State University.

Anyone who has a chronic disease or condition that places them at higher risk — such as obesity, diabetes, heart disease or cancer — might want to get another booster dose now, both said.

But those 50 and over who don’t have additional risk factors might find it better to wait and time a second booster with a possible fall wave in mind, assuming cases don’t spike sooner, the doctors said.

“The optimal timing I’m not sure about,” Nagpal said. One consideration is that it takes from one to two weeks of receiving the shot for the dose to take full effect. Antibodies are active for four or five weeks, then they wane, he said.

It’s much more important, Carson and Nagpal said, for people to be fully vaccinated and to receive a first booster dose than a second booster dose.

“I think the fourth shot, second booster, is a far, far lower priority,” Carson said.

In North Dakota, 40% of the population 18 and older remains unvaccinated against COVID-19 — getting that population immunized with a first booster, he said, is “way more important” than for everyone 50 or older to get a second booster.

In Minnesota, 30% of the total population is unvaccinated against the coronavirus, and in South Dakota, 28% have not received a shot of the vaccine.

“If you haven’t had a vaccination, get started,” Carson said.

Getting more of the population vaccinated, Nagpal agreed, should be the priority. “I think the overall goal should be that we need more people vaccinated,” he said.

Still, Carson said he “strongly encourages” those 50 and older — especially those with underlying health conditions that put them at higher risk — to get a second booster dose.

On the other hand, those who have been fully vaccinated and had a “breakthrough” COVID-19 infection have excellent protection against reinfection, Carson said. “If you’ve had a breakthrough, I don’t think you need anything, at least now.”

Individual circumstances are important in guiding whether and when a fourth dose is advisable, Nagpal said. “It’s a little hard making a blanket recommendation right now,” he said.

Those who are eligible for a second booster but uncertain about when to get the shot can probably wait, while keeping an eye on how much the virus is spreading in their community, Carson and Nagpal said.

“I think most people who have had three doses are probably in pretty good shape,” Carson said. For them, a fourth dose would be “a non-urgent discussion with your own physician regarding your own risk,” he said.

Unlike earlier in the pandemic, antiviral pills now are available to treat those with COVID-19 who are at risk of developing severe symptoms, Carson and Nagpal said.

“We’re just in a much better place than we were before, and I think people can take a little bit of a breather with this,” Carson said.

So far, the omicron subvariant that recently became the dominant virus strain doesn’t seem to be causing major infection spikes in the United States. The omicron subvariant has been found in North Dakota and Minnesota.

“I am cautiously optimistic we are not getting any big spikes,” Carson said. Because the omicron wave caused so many infections, much of the population now has some degree of protection from previous infection or vaccination, Carson and Nagpal said.

“Our immunity wall is really getting much higher now,” Carson said.