Vaccine rollout continues after the black winter wave, and with cases of coronavirus declining, the end of the epidemic seems imminent. In reality, how soon can we get there?
One answer lies in herd immunity, to the point when enough people are immune to the virus that it no longer spreads through that population. Getting there depends not only on how fast we can get vaccinated, but also on other factors, such as how many people are already infected and how easily the virus is spread.
An estimate for the path of mob immunity
This chart shows the current path of herd immunity in the United States, based on a model developed by the public health research group PHICOR. He sees the number of people The complete vaccine And combined with estimates of the number of people who have been infected and have improved in size Total immunity.
When the orange line crosses the blue area, it means we have entered Bunch immunity range. The exact threshold for flock immunity to coronavirus is unknown, but recent estimates range from 70 percent to 90 percent.
At first glance, this seems like pretty good news – under these assumptions, we can reach the crowd’s immunity as early as July. But a lot can happen between now and then. The speed and intensity of vaccination and how long the immunity lasts are big factors. The rise of new virus types and how we respond to them will also affect the pathway of animal husbandry.
In most scenarios, before the mob’s immunity arrives, millions more will be infected and tens or millions will die.
What if we speed up vaccinations?
More than 15 million people have been fully vaccinated, and U.S. Currently runs about 1.7 million shots per day. Some experts say that with the approval of new vaccines, we will be able to double this pace by April. (Because existing vaccines require two doses at weekly intervals, therefore, the number of people receiving the full vaccine each day is low.)
The more people we vaccinate, the faster we can reach the threshold for herd immunity.
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If the speed increases to 3 million shots per day, we can reach the mob immunity threshold from there. May. At that time, 90,000 People can die from the virus.
It is important to note that the orange line for total immunity is based on the assumption that people are already infected, including those with immunity from diagnostic cases. When the pink line for vaccination falls into that range we can be more certain about reaching the herd immunity. But in the event that a new but less effective vaccine comes along, we will not be able to reach the threshold by vaccination alone.
And the model comes with some other warnings. Many are still unaware of how long immunity from vaccines will last, or how well these vaccines will protect against new types of viruses. Estimates also suggest that the vaccine prevents infection rather than simply reducing the severity of coronavirus symptoms.
“There are still key pieces of missing information that could have an impact on what could happen to the epidemic in the coming months,” said Dr. Bruce Y. Lee, a professor of health policy at New York City University, who is leading PHICOR’s research efforts. Said. “A lot of people will lose their immune system in the next few months after recovering from an infection, making many more victims of the virus again.”
Some experts argue that reducing mortality and serious illness is a better and more achievable goal than whole mass immunization, and that increasing vaccinations is still the best way.
What if we bridge the social gap?
Measures such as wearing masks and social distance have been shown to be effective in slowing the spread of the virus. As more people are vaccinated, it is inspiring to simplify the precautions.
While this means that the sooner we reach the mob immunity as more people get sick and develop antibodies, that momentum will come at a terrible cost.
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If we end the sanctions in April, we can reach the mob immunity threshold by then. June. But at the time, 170,000 The virus can kill more people.
Caution is especially important when new types of viruses emerge. If social distance measures are not followed, a strong virus can quickly kill and kill thousands of people before they get vaccinated.
What if more contagious infections spread?
A more contagious type of virus, such as the virus first identified in Britain, which is now prevalent in the United States, could further complicate the pathway to animal immunity.
If the virus becomes more contagious, the threshold for herd immunity will rise. Vaccines can be difficult to keep in motion and precautions will be even more necessary to prevent spread.
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More infectious variants will spread faster and raise the threshold immunity threshold. We can still expect to reach animal immunity July, But new deaths can double Is 200,000 People.
The spread of new virus types makes it impossible to set a definite date for when we will reach the flock’s immune system or when the epidemic will end. There is a chance that the mutation could lead to a version of the virus that does not respond to existing immunity, and lead her to resume the journey to animal husbandry.
Dr. Lee said the coronavirus has a relatively high conversion rate and new types of viruses are likely to continue to emerge. “The question will be how these types can be different,” he said. If some type of virus stops responding to the vaccine, “then it will be a matter of determining whether a new vaccine needs to be produced.”
Method
The model used in this article was adapted from one originally published in the American Journal Pref Preventive Medicine and has been updated to reflect the most recent estimates of coronavirus prevalence, transmissibility and severity as of February 16.
To adapt the model for the web, The New York Times published Public Health Informatics, Computational and Operations Research or PHICOR: Bruce Y. Lee, Sarah M. Bartsh, Kelly J. O’Cia, Patrick T. Wadlock and Mary C. Ferguson.
Vacc historical case data, the best available estimates of virus transmissibility, and the effect of social distance measures are used to estimate new cases of vaccine administration and the future course of death. Vaccine immunity represents the share of people who are fully vaccinated and have the immune system, taking into account the effectiveness of available vaccines.
The model assumes that immunity lasts indefinitely and that vaccination prevents infection rather than simply reducing the severity of coronavirus symptoms. It does not account for the immunity that can be obtained from a single dose of the vaccine.
It is believed that the vaccine prevents infection against current and future coronavirus types by 90 percent of those who receive the full vaccine, and 80 percent of the population is eventually fully vaccinated.
