Will NH Reach COVID-19 Herd Immunity? Hard to Say | Local News

Since the beginning of the pandemic of the new coronavirus infection (COVID-19), both health authorities and doctors have set “herd immunity” as a goal to overcome the crisis.

This occurs when the majority of the community is immune to the disease (usually by vaccination) and is less likely to spread further. In New Hampshire, nearly half of New Hampshire residents are fully vaccinated with COVID-19, and cases are consistently declining.

According to health experts, it’s hard to say.

“There is no objective definition of herd immunity, and as we say, it’s a continuous function rather than a threshold. It’s not like a lamp switch. It’s more like a dimmer. “It’s a thing,” said Dr. William Schaffner, a professor of medicine in the Department of Infectious Diseases at Vanderbilt University in Tennessee.

The percentage of the population that needs immunity to achieve herd immunity depends on the disease and its infectivity.

For example, measles spreads so easily that an estimated 95% of the population must be vaccinated to obtain herd immunity, according to the World Health Organization (WHO). The remaining 5% is also protected because the virus cannot spread.

Most estimates of COVID-19 set the number to be 70-80% immunized. However, due to hesitation in vaccines, the emergence of new variants, and delays in vaccination of children, many healthcare professionals say it is unclear whether herd immunity will be achieved against COVID-19. ..

“The question is,” What is your goal? ” Well, to reduce really low levels of viral infections and very low levels of cases so that you can say “yes, this was in control”, you need to get up to about 80%. There is a percentage of people who have been vaccinated, “said Schaffner.

Dr. Michael Lindberg, who retired in April after serving as chief medical officer at the Monadnock Community Hospital in Peterborough, said it was also important to know how many people were already infected with the virus inside and outside New Hampshire. It was.

“The number we don’t know is that any part of the population was infected with the virus and was infected and didn’t know it,” he said. For example, “if 20% of the population is infected but unaware of it, it can push us up to 70%,” he continued. “But I don’t think we’re there yet.”

Lindberg added that herd immunity not only keeps the infection low, but also helps prevent more COVID-19 mutations from occurring.

“Over time, as it spreads, there is a risk of developing more variants … every time the virus jumps to another person, there is a chance of mutation. I don’t want to see it, “he said.

Some variants of COVID-19 are considered highly contagious and may increase the risk of infection, hospitalization, and death. In addition, new variants may be resistant to vaccination.

Dr. Daniel Pali, the current chief medical officer at Peterboro Hospital, said recent relaxation of safety protocols, especially considering the current number of cases, such as allowing vaccinated people to take off their masks indoors. Said that it was rational.

However, he said the ability to achieve COVID-19 herd immunity was “complex”.

“I’m not sure, but to be honest, it seems unlikely that we will,” he said. “We do not yet fully understand COVID herd immunity and are not sure if it is achievable. [get] Completely remove the virus. “

Anyway, he and Lindberg emphasized the importance of getting people vaccinated.

“We don’t want the general public to feel that we shouldn’t continue vaccination because we never reach this magical herd immunity. The purpose is to prevent transmission, protect vulnerable people, hospitalize and die. To reduce the rate, “he said. “That’s an idea we should pay attention to.”