The decline of Covid-19 preceded the vaccine.But we need a jab to get the job done

AWith the reduction of coronavirus infections in the United States, it seems appropriate to celebrate the victory of the vaccine against the virus. But how credible is the vaccine? Less than you would expect.

Don’t get me wrong. I believe in vaccines. I get vaccinated as soon as I qualify and I am 100% behind the goal of getting vaccinated for everyone on the planet. However, other factors are also working to calm the pandemic.

Following the previous pandemic pattern, a sharp decline in new cases of Covid-19 began long before a significant number of people were vaccinated.

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Almost 50 years ago, medical sociologists John and Sonya McKinley I examined the mortality rate From 10 serious diseases of tuberculosis, scarlet fever, Haemophilus influenzae, pneumonia, diphtheria, whooping cough, measles, smallpox, typhoid fever, polio. In each case, new treatments or vaccines allegedly overcome it were introduced long after the disease had declined.Recently, historian Thomas McKeown OK Deaths from bronchitis, pneumonia, and the flu began to decline rapidly 35 years before the allegedly conquered new drug was introduced.

These historical analyzes are relevant to the current pandemic.

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New cases of Covid-19 peaked in early January 2021. Since then, the number of cases has decreased from more than 300,000 per day on January 8th to about 55,000 on February 21st. The vaccine was first granted an emergency use authorization towards the end of December 2020. On February 21, only 5.9% of Americans received two shots, a decrease of 82% in new cases.

Indeed, the coronavirus vaccine is a remarkable achievement. However, even a vaccine that is 95% effective cannot be fully trusted if introduced behind a naturally retreating epidemic. Timing is everything.

There are two ways to boost immunity: natural infection and vaccination. The best explanation for the rate of decline in Covid-19 seems to be previous infections, which vary considerably from state to state.

Individuals diagnosed with Covid-19 are just the tip of the iceberg.Estimates are different, but the latest Research According to a report from the National Institutes of Health, about 5 of each confirmed case were infected with SARS-CoV-2, the virus that causes Covid-19. Multiplying a known case by 5 gives an estimate of the number of people who may be infected. I performed a simple calculation of what I call the innate immunity rate by dividing the estimated number of people naturally infected with SARS-CoV-2 by the state’s population.

By mid-February 2021, an estimated 150 million people (30 million x 5) in the United States may have been infected with SARS-CoV-2. By April, we estimated that the innate immunity rate would exceed 55% in 10 states: Arizona, Iowa, Nebraska, North Dakota, Oklahoma, Rhode Island, South Dakota, Tennessee, Utah, and Wisconsin. At the other end of the continuum, innate immunity is less than 35% in District of Columbia, Hawaii, Maine, Maryland, New Hampshire, Oregon, Puerto Rico, Vermont, Virginia, and Washington. Estimated.

The table below summarizes how the two groups, high and low natural infection rates, differ. By the end of 2020, new infections are already rapid in almost all 10 states where the majority may have had innate immunity long before more than a small percentage of Americans were fully vaccinated. It was decreasing to. In 80% of these states, there were days when new cases peaked before vaccines became available.

In contrast, in the 10 states with previously lower infection rates, new uptics were much more likely to occur in Covid-19 cases in March and April. The date with the highest number of new cases occurred before the vaccine was available in only 30% of these states. By the end of May, states with fewer new infections had significantly lower vaccination rates than states with more new infections.

In other words, we have also experienced states with low innate immunity that have vaccinated more citizens, such as Oregon, Vermont, and Washington. More New Covid-19 cases. In addition, despite low immunization rates, innate immunity states such as North Dakota, Tennessee, and Utah had fewer cases due to an increase in the number of citizens protected by innate immunity from previous infections. There is a possibility.

Public policy may also have played an unexpected role. In the 2020 presidential election, Donald Trump carried seven of the ten innate immunity states, and Joe Biden carried all ten low innate immunity states. Of the 10 states with high innate immunity, 90% did not have an active mask policy, while 90% of states with low innate immunity had a mask policy until May.

Data from New York Times, Values ​​up to May 2021

What’s wrong? First, the enacted mask-related policy states that there were few new cases of Covid-19. That’s certainly good news. However, there may have been a downside. Unvaccinated people may have become vulnerable to SARS-CoV-2 because fewer people have acquired innate immunity due to masks and other obligations that have successfully reduced infection. Conversely, states without mask policies suffered from higher infection rates, provided more innate immunity, and provided more protection before vaccines became available.

Vaccines and previous infections are alternative routes to immunity, but vaccines are a much safer route to it. The cost for some states to achieve high innate immunity was intolerable illness, hospitalization, and grief of death. It is unacceptably irresponsible to suggest that people are at risk of getting infected to achieve immunity.

To prepare for a future pandemic, the United States (and other countries) needs to learn what really happened during this pandemic process. The answer may not be simple, as many nuances are superimposed on the ever-changing trends.

For example, in contrast to my analysis, The Washington Post Reported on June 14 Coronavirus infections are decreasing in vaccinated areas and increasing in unvaccinated areas. Post analysis is correct: There is a reasonable correlation between current state-level vaccination rates and the latest reports of new cases. But it ignores long-term trends.

In states with low innate immunity, despite receiving more vaccines, Covid-19 is more likely to surge in the spring. As the pandemic receded, the decline in low innate immunity could have seemed greater as it had fallen from the higher spring peaks. By December, most states with high innate immunity have low rates of new cases and little room to observe a decline.Set of graphs You can get it from here..

Some analyzes also focus on small geographic areas. In Sweetwater County, Wyoming, only about 27% of the population is fully vaccinated, media Note. The county recently led Wyoming for an increase in new cases. Wyoming is now leading the United States with new infectious diseases.But in Sweetwater County 42,343 residents. A small (possibly temporary) change in the number of cases can manifest itself as a large percentage of change.

In contrast to the proposed spikes New York Times The 7-day average for new cases of Sweetwater has been relatively stable over the past few months, indicating a decline from the recent June 1 highs. Although vaccination rates across Wyoming are very low, new cases have declined by mid-February.Many people may have been vaccinated — and Remains fairly stable Throughout spring.

Epidemiology is rarely simple, and it takes time to sort out these conflicting interpretations.

But one trend seems clear. As with previous pandemics, the sharp decline in new cases preceded widespread distribution of the vaccine. The vaccine deserves praise for the reduced infection rate of Covid-19, but the protection against natural infections is underestimated.New evidence is that previously infected people are effective Durable immunity It Rival or excess Vaccine benefits.

Historians may look back on this pandemic and report that the work of its solution should be shared by vaccines, innate immunity, and other public health measures. However, the vaccine did not cause a reduction in Covid-19 cases, but it is the best tool available to ensure that the smoldering fire of the vaccine is extinguished.

Robert M. Kaplan is a faculty member at the Clinical Excellence Research Center at Stanford Medicine and an emeritus professor at the UCLA Fielding School of Public Health.