Can the COVID-19 vaccine lead us to herd immunity? “The jury is definitely not out yet.”

Los Angeles – The purpose of the vaccination campaign against COVID-19 is herd immunity. This is where the virus loses its place because few people are susceptible to infection.

In the early days of the pandemic, epidemiologists estimated that about two-thirds of the US population would need to be vaccinated.

Now, many of those same experts say the numbers are almost certainly too low.

“If you really need herd immunity and you need to protect the whole country, you need to vaccinate about 75-85% of the country,” said Dr. Anthony Fauci, the country’s top infectious disease official. Said. Reporter last week. “I think it’s even closer to 85 percent.”

This change reflects a deeper understanding of how the virus spreads. That is, the virus jumps from person to person more easily than previously thought.

The question of how many people have to be vaccinated is very important as the world embarks on the largest vaccination campaign in decades.

The purpose of vaccination is not only to protect the individual who receives it, but also to cover the majority of the population enough for the fire to start running out of fuel.

If too few people are vaccinated, the virus will continue to find enough new hosts to grow itself. And if it continues to stress the health system, slows economic recovery, requires social distance, and vaccines become ineffective over time, it can surge again.

Whatever the herd immunity threshold, public health authorities face major challenges.

In an early December poll by the Associated Press-NORC Public Relations and Research Center, 46% of American adults were expected to be vaccinated, but 26% declined and 27% were still undecided.

One research group found that the message of vaccination prevention on social media has tripled since the pandemic began.

Certain disorders may be vaccinations of children and teenagers who have not been particularly severely affected by the pandemic and whose vaccine is still being tested. However, in 22% of the US population, it is important for all efforts to achieve herd immunity and return to normal life.

When epidemiologists first aimed to model the number of people who needed vaccination to drive the coronavirus to extinction, they compared early infection trends with trends in other recent influenza epidemics. Did.

They pointed out that the coronavirus has a long incubation period, is asymptomatic, and is highly contagious. The pandemic is estimated to last 18 to 24 months.

“It’s probably unstoppable until 60% to 70% of the population acquires immunity,” said a report released by an infectious disease expert in April.

There are two ways to immunity. You can either get infected with the virus and recover, or you can get vaccinated. Neither is a guarantee.

Based on clinical trial data showing that the efficacy of the two licensed vaccines, Pfizer and Moderna, is excellent but still incomplete, the herd immunity threshold rises to about 74%.

But experts say the calculations are still too simple.

“While these numbers are useful for thought experiments, they do not represent anything that is likely to be a way to control the virus and its effects,” said Harvard epidemiologist Mark Lipsich. “To provide some kind of magic number, we need to make very strong assumptions about these vaccines.”

Many factors can be involved. As the virus becomes more contagious, the threshold for herd immunity rises.

Targets may vary from location to location. In less populated areas where people adhere to social distance guidelines, fewer people need to be vaccinated to burn the virus.

William Hanage, an epidemiologist at Harvard’s Center for Infectious Disease Dynamics, said: “From now on, it will be like we have been studying for a very long time.

Next is the vaccine itself.

They were approved based on rapid-fire clinical trials showing that recipients are very unlikely to develop symptoms of COVID-19, but the vaccine actually infects or infects people. I didn’t decide whether to prevent it from happening.

The extent to which the vaccine prevents infection is very important in the equation for calculating herd immunity. In bad-case scenarios, vaccination alone cannot achieve herd immunity, as vaccines have little effect in stopping infection.

“At this point, the jury is definitely not out yet,” Lipsic said. “If you have to guess, there is a component of herd immunity. I don’t know how dramatic it will be.”

Reaching herd immunity can prove to depend on everyone, not just the number of vaccinated people. Vaccination of people who are most likely to spread it, for example, those who live or work nearby, is more likely to contain the pandemic than vaccination of people who live in relatively isolated areas. May do much more.

Given all these unknowns, Fauci made his estimate 85% – and said it could be even higher.

The cost of not achieving herd immunity is considerable. If the virus continues to spread, even vaccinated people will be infected with COVID-19. Hospitals continue to face a proliferation of viruses, exhausting resources and impairing their ability to treat heart attacks, strokes and other emergencies.

Meanwhile, overall quality of life will continue to deteriorate. Even for vaccinated people, schools, offices and restaurants remain closed.

According to experts, social distance and wearing a mask stay here until the virus circulates at an abnormally low level (until the risk of infection is nearly zero).

The final answer to the question of how many people need to be vaccinated will not be known until herd immunity is actually achieved. When epidemiologists begin to drop test positive rates to very low numbers, it’s a way for them to know that the campaign is working.

However, with the exception of smallpox, the viruses that afflict humans have never been completely wiped out. Experts have been suffering from polio for decades and have recently been struggling in conflict areas where vaccination campaigns have been suspended.

They emphasize that in the age of globalization, herd immunity must ultimately take into account almost every corner of the globe – pathogens everywhere remain a threat everywhere.

“I think it’s very unlikely that we can eradicate this virus,” Hanage said. “In reality, you have to accept it.”

“But we should be able to live without seriously damaging our lives, without leading to surges or massive over-death that damage our healthcare. That is what we aim for. To be. Achieve. “

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