đź”’ Covid-19 will soon be endemic – With insights from The Wall Street Journal

As infectious-disease physician and UC professor Dr Monica Gandhi writes in the republished piece below, Covid is transitioning from epidemic to endemic. Safe vaccines produced in record time played a huge role in this. So, too, has the rapid spread of, in particular, the Delta variant which delivers natural immunity to the infected, most of whom don’t even know they’ve had the coronavirus. So, the heated debate over the virus will temper. Still, lessons from unwitting mis-steps should be heeded. It’s wrong to waste a good crisis. Particularly when it has been as costly as this one. – Alec Hogg

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Covid Will Soon Be Endemic, Thank Goodness

Widespread immunity, vaccinated and natural, will bring control and a full return to normal.

Sept. 30, 2021 1:50 pm ET

Covid-19 will soon become endemic—and the sooner the better.

An epidemic causes widespread disease in a region. A pandemic affects multiple countries or continents. A disease becomes endemic when it is manageable—defined, for instance, as not causing an undue burden on hospitals or other healthcare resources—but is unlikely to be eliminated because of the pathogen’s inherent properties.

Australia, China and New Zealand have pursued “zero Covid” policies that aim at elimination (reducing incidence in a region to zero) or even eradication (world-wide elimination). That goal is unrealistic. Smallpox is the only human disease that has ever been eradicated. The smallpox virus has had four properties that made it eradicable: the lack of an animal reservoir, clear and distinctive signs and symptoms, a short period of infectiousness, and both lifelong natural immunity after survival and a highly effective vaccine.

SARS-CoV-2, by contrast, is unlikely to be eradicated. It has animal reservoirs, a high level of transmissibility (especially of the Delta variant), and overlapping symptoms with other respiratory diseases. It has, as well, a prolonged period of infectiousness, caused by its propensity to spread from asymptomatic or presymptomatic carriers.

That’s why reducing the disease from epidemic to endemic is the best case—one that will allow a full return to normal. Many ineradicable infections are controlled by vaccination and treatment. Measles, a highly transmissible respiratory virus, created high levels of immunity among adults who were exposed as children. But until a vaccine was developed in 1963, some nonimmune adults died every year. Pertussis (whooping cough) is caused by a highly contagious bacterium (with syndromes that overlap some respiratory viruses), but it is controlled in the U.S. through vaccination of children, antibiotics and other treatments. (Vaccine hesitancy among parents in the U.S., however, has led to outbreaks of both pertussis and measles over the past decade.)

Officials tried a wide array of measures to control SARS-CoV-2: masks, social distancing, lockdowns, travel restrictions, ventilation, testing, contact tracing. These had varying levels of success but ultimately proved insufficient to control the virus in a sustained way. That will require widespread immunity. Fortunately, safe and effective vaccines were developed for SARS-CoV-2 in record time. These vaccines are the key to turning Covid-19 into an endemic but controlled communicable disease.

Control means the reduction of serious disease, not of asymptomatic or mild cases. Since the vaccines are remarkably effective in preventing severe disease from Covid-19—what made SARS-CoV-2 a global threat—they can serve as the conduit for control.

Antibodies generated by the vaccines will naturally wane, but the vaccines trigger the creation of B cells that get relegated to our memory banks, and these memory B cells produce high levels of neutralizing antibodies if they see the virus again, even in variant form. Memory B cells are long-lasting. A 2008 Nature study found that survivors of the 1918 flu pandemic were able to produce antibodies when exposed to the same influenza strain nine decades later. T cells (also put into cell memory) generated by the vaccines protect us from severe disease and are unfazed by variants.

What would endemic Covid-19 look like? If we can tamp down the virus’s circulation and reduce its ability to cause severe disease through widespread vaccination, the world will be able to return to normal. Outbreaks of severe disease will occur among populations unwilling to be vaccinated, as we see with measles and pertussis, but mandates can help increase vaccination rates.

As circulation of the virus decreases with increasing immunity, Covid-19 will go the way of other respiratory viruses over which we have control. We will test those who arrive at the hospital for a variety of infections—including influenza, Covid-19, respiratory syncytial virus (mainly in children) and bacterial pathogens—and tailor treatments to the infectious agent. Moderate respiratory symptoms of Covid-19 in the outpatient setting may be treated with monoclonal antibodies or outpatient antivirals (under development), and mild symptoms (like other common colds) won’t require treatment.

The burden of disease a country is willing to accept will depend on its priorities: Denmark dropped all restrictions at a 74% vaccination rate and low cases on Sept. 10, and Norway dropped them on Sept. 25 at a 67% vaccination rate. Many U.S. states had an undue burden of hospitalization during the Delta wave, although California is keeping restrictions in place despite low hospitalization and high vaccination rates. We will need to accept that the noneradicable disease is endemic. A low burden of disease should facilitate the transition.

Although SARS-CoV-2 has proved unpredictable, no virus in history has ever continued to evolve to higher pathogenicity. As we learned from HIV, mutations usually incur costs to viral fitness or render the virus weaker. No vaccine-preventable or immunity-inducing infection has ever raged on as a pandemic indefinitely. An endemic virus doesn’t require continuing isolation and other restrictions; defanging SARS-CoV-2 by stripping it of its ability to cause severe disease through immunity will relegate it to the fate of the other four circulating cold-causing coronaviruses. The key to this normalcy is immunity. With a highly transmissible variant driving up immunity in the unvaccinated and bolstering it in the vaccinated, Covid-19 will inevitably make the transition from epidemic to endemic.

Dr. Gandhi is an infectious-disease physician and professor of medicine at the University of California, San Francisco.

Appeared in the October 1, 2021, print edition.

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