Herd immunity is back in headlines as South Carolina prepares for next phase

The next vaccine rollout for South Carolina will be Phase 1C

The concept of “herd immunity” is once again in the headlines as South Carolina prepares to transition to the next phase of the coronavirus vaccination rollout. While not every scientist and doctor believes in it, it’s generally accepted as the point when a virus cannot easily spread within a population because most people are immune to it.

Herd immunity can be achieved solely through natural infection, but this requires a virus that does not mutate or mutates very slowly.

Most often, it’s achieved through vaccinating huge numbers of people in a relatively short time span, combined with people who have natural immunity because they’ve infected before.

Since the first smallpox vaccine was invented in 1796, humans in developed countries have been able to achieve herd immunity against many severe diseases. Smallpox itself was eradicated in 1980.

There are still many questions about immunity against COVID-19, but achieving it has been the goal of health leaders since the early days of the pandemic. Here’s what we know so far:

How many people need to be vaccinated to obtain herd immunity to COVID-19?

The exact level of immunization is still unclear, but health leaders believe it’s at least 70% of the population, including both adults and children. Since people 15 and under are not yet able to receive a vaccine, achieving it quickly will require more adults to roll up their sleeves.

As of Wednesday, 21.5% of South Carolinians had gotten at least one vaccine dose. It’s estimated that six out of every 10 adults who have not yet been vaccinated will need to make an appointment for the state to have a chance at herd immunity.

Is COVID-19 herd immunity even possible?

It depends on how quickly the virus mutates once many people are vaccinated. The world is already experiencing multiple variants, but none so far have proved to make the vaccines ineffective. Should one occur, herd immunity would be more difficult to achieve. The rate at which the virus changes and adapts could determine whether a vaccine is good for life, or routine boosters would be needed like tetanus or flu shots.

It will also depend on how much of the population is hesitant to receive the vaccine. While hesitancy is dropping and scientists and doctors agree the shots are safe and effective, there will always be some people who will refuse to be vaccinated, or who may be allergic to an ingredient.

“Measles is one of the most infectious viruses we’ve ever known, and we’ve achieved herd immunity with that to the extent that measles is actually considered to be eliminated in the United States,” DHEC’s Michael Kacka said, as a reminder for why it’s important that people participate in the rollout.

If I’ve already had COVID-19, do I still need to get the vaccine?

Yes. Scientists aren’t sure how long natural immunity lasts, with some believing it’s lifelong and others capping it at six months. More research will be needed before an answer is decided. However, a vaccine will still provide an extra layer of protection, and in some cases it has been shown to boost someone’s immunity even more after they’ve had COVID.

If we reach herd immunity, does this mean communities will be able to gather once again?

That’s the hope! The CDC has already updated their guidelines to say that vaccinated people may hang out with other vaccinated people.

Once we reach herd immunity, is the pandemic considered over? If not, when?

No, but it has nothing to do with us. The pandemic isn’t over until everyone has reached herd immunity, including poorer nations where vaccines aren’t as prevalent. Wealthy developed nations have gobbled up most of the supply so far, while some countries have not yet received a single dose. Officials say it could take years before the supply of doses is great enough that every country is able to achieve herd immunity.

Why does this matter? As long as the virus is still spreading through communities, be it in South Carolina or Sierra Leone, it has more chances to mutate and become resistant to the vaccines. Some leaders are already beginning to recognize this and send shipments of doses to neighboring countries or allies.

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