The need for COVID-19 booster shots should not come as a surprise, Dr. Paul Carson told North Dakotans Thursday during a virtual town hall Thursday afternoon. Carson is director of the Fellow of the American College of Physicians with North Dakota State University and was one of several experts speaking during the event.

Boosters are common for many vaccines, Carson pointed out. Tetanus shots are given about every 10 years, while the HPV vaccine is two to three doses over six months. Hepatitis B has three doses over a year, pneumococcal vaccine has four doses over a span of 15 months, and the polio vaccine is four doses over four to six years.

“We often need boosters to optimize or maximize our immune response,” he said. “This often works to give very prolonged immunity.”

There could be multiple factors that would contribute to waning effectiveness for the COVID-19 vaccine, Carson said.

“We know that there’s sometimes a decline in our immune response over time,” he said. “So the further out we get from, you know, our original vaccination, our immune system can wane.”

It’s also possible the Delta variant has changed just enough that antibodies produced in response to the original spike protein, modeled off the Alpha variant, are no longer as effective.

“And we know that as people age, they might not make as good of an immune response,” Carson said. “A lot of those things overlap. I mean, the first people to get vaccinated were the elderly, so they are the furthest out from the vaccine, and that time away from that initial vaccine is when the Delta variant started to circulate, so all of those things might come into play.”

Data from New York seem to suggest, however, that waning effectiveness is a function of time, more than anything else, Carson said. That same data also shows that effectiveness against hospitalizations still remains high for the existing COVID-19 vaccinations — in the 90 to 95 percent range.

“We don’t care so much about preventing colds and mild flu-like illnesses,” Carson added. “We care about preventing serious illness.”

Breakthroughs

North Dakota has vaccinated 300,000 people so far and has 4,600 breakthroughs, or about 1.4 percent of the vaccinated population.

“Those, for the most part tend to be very mild, but not all,” Carson said. “We’ve had over 200 hospitalizations in those breakthrough cases. That amounts to .065 percent of the vaccinated population. And there’s even been some deaths. Thirty-two deaths. That amounts to .0095 percent of the vaccinated population.”

Severe cases among vaccinated individuals appear to be occurring mainly in elderly nursing home residents or people with several underlying medical conditions, which range from diabetes to obesity. This is another reason why booster shots are being recommended for those over the age of 65 or those over age 50 with underlying conditions.

Despite breakthroughs, North Dakota numbers still show great vaccine effectiveness for most people when it comes to serious illness, Carson added, and the rate of infections remains much lower for vaccinated versus unvaccinated individuals.

“Overall, we now see about one out of 72 fully vaccinated people in the state have tested positive for the virus,” he said.

That compares to a rate of 1 out of 11 for unvaccinated people.

Data does show that those who catch COVID despite vaccination still tend to have a shorter duration of illness. It’s also harder to culture virus from those individuals. Both factors suggest vaccinated individuals are generally still less likely to transmit the virus to someone else, even when they suffer a breakthrough case.

Looking at hospital data from Sanford Health System, which has made its data public for COVID-19 hospitalizations, shows that vaccines are still very effective when it comes to preventing serious COVID-19. Sanford has 158 hospitalized people across all its hospitals, of which only 12 were vaccinated people. Of the 158 hospitalized, 45 in the ICU. Only two of those had been vaccinated. And there are 28 people on ventilators, none of them vaccinated.

“Overall, they have steadily seen in their system, 90 to 95 percent of people in the hospital, in the ICU, or on a ventilator are unvaccinated,” Carson said. “So, as far as health systems like Sanford in North Dakota, in the hospital, it does still remain a pandemic primarily of the unvaccinated.”

Safety data looks good for boosters

How long a booster shot will prolong immunity to COVID-19 is not yet known, but data that Pfizer submitted to federal authorities showed the third booster shot increased antibody levels five to 12-fold, Carson said.

Clinical data from Israel, which is ahead of the United States on vaccinations, was also presented to the FDA when that agency was deciding whether it would recommend booster shots. That data showed a drop from 85 infections per 100,000 down to 8.8, Carson said.

“This basically restored that vaccine effectiveness to 91 percent against any infection, and about 95 percent against severe illness,” he said.

The data so far do not show any increase in adverse reactions for the 12,000 or so immunocompromised people in the U.S. who have already been given a third COVID-19 shot.

Similarly, in Israel, where about 2.8 million boosters have been administered to ages 12 and up, side effects do not appear to be any more prevalent than for the two-doses. In fact, they were less prevalent for what were already rare cases of myocarditis seen in younger males under age 30.

Long-term care ready for boosters

State officials have already surveyed the 211 long-term care facilities in North Dakota to determine whether each facility has a plan in place for administering booster doses.

“Facilities have been encouraged to contact their primary vaccinator and are scheduling their booster dose clinics, I should say, as soon as possible,” North Dakota Long-term Care Association representative Vanessa Raile said. “You know they understand the goal to vaccinate the residents and staff as soon as possible.”

More and more of North Dakota’s long-term care staff are also getting vaccinated or taking booster shots, Raile added.

Immunization Program Manager Molly Howell said while the state is taking very seriously the need for booster shots, she wants people to realize that it’s not going to be what ends the pandemic.

“It will have a small impact,” she said. “But really what’s impacting our hospital capacity, what’s causing the majority of the cases, are unvaccinated individuals and so people choosing to be vaccinated who are not yet vaccinated will have the greatest impact on the pandemic and is the priority.”

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