How will Covid end? Experts look to past epidemics for clues

Two years into the Covid-19 pandemic, most of the world has seen a dramatic improvement in infections, hospitalisations and death rates in recent weeks, signaling the crisis appears to be winding down. But how will it end? Past epidemics may provide clues.

The ends of epidemics are not as thoroughly researched as their beginnings. But there are recurring themes that could offer lessons for the months ahead, said Erica Charters of the University of Oxford, who studies the issue.

“One thing we have learned is it’s a long, drawn-out process” that includes different types of endings that may not all occur at the same time, she said. That includes a “medical end,” when disease recedes, the “political end,” when government prevention measures cease, and the “social end,” when people move on.

The Covid-19 global pandemic has waxed and waned differently in different parts of the world. But in the United States, at least, there is reason to believe the end is near.

But this pandemic has been full of surprises, lasting more than two years and causing nearly 1 million deaths in the US and more than 6 million around the world. Its severity has been surprising.

Some experts offered takeaways from past epidemics that may inform how the end of the Covid-19 pandemic may play out.

Pandemics don’t end with a disease ebbing uniformly across the globe. A pandemic ends by becoming multiple (regional) epidemics,"

Flu

Before Covid-19, influenza was considered the most deadly pandemic agent.

A new flu in 2009 caused another pandemic, but one that turned out not to be particularly dangerous to the elderly — the group that tends to die the most from flu and its complications. Ultimately, fewer than 13,000 US deaths were attributed to that pandemic.

The WHO in August 2010 declared the flu had moved into a post-pandemic period, with cases and outbreaks moving into customary seasonal patterns.

In each case, the pandemics waned as time passed and the general population built immunity. They became the seasonal flu of subsequent years. That kind of pattern is probably what will happen with the coronavirus, too, experts say.

“It becomes normal,” said Matthew Ferrari, director of Penn State’s Center for Infectious Disease Dynamics. “There’s a regular, undulating pattern when there’s a time of year when there’s more cases, a time of year when there’s less cases. Something that’s going to look a lot like seasonal flu or the common cold.”

HIV

In 1981, US health officials reported a cluster of cases of cancerous lesions and pneumonia in previously healthy gay men in California and New York. More and more cases began to appear, and by the next year officials were calling the disease AIDS, for acquired immune deficiency syndrome.

Treatments that became available in the 1990s turned it into a manageable chronic condition for most Americans. Attention shifted to Africa and other parts of the world, where it was not controlled and is still considered an ongoing emergency.

Pandemics don’t end with a disease ebbing uniformly across the globe, Charters said. “How a pandemic ends is generally by becoming multiple (regional) epidemics," she said.

Covid-19

The Geneva-based WHO declared Covid19 a pandemic on March 11, 2020, and it will decide when enough countries have seen a sufficient decline in cases — or, at least, in hospitalisations and deaths — to say the international health emergency is over.

The WHO has not yet announced target thresholds. But officials this week responded to questions about the possible end of the pandemic by noting how much more needs to be accomplished before the world can turn the page.

Covid-19 cases are waning in the US, and dropped globally in the last week by 5%. But cases are rising in some places, including the UK, New Zealand and Hong Kong.

People in many countries need vaccines and medications, said Dr Carissa Etienne, director of the Pan American Health Organization, which is part of the WHO.

In Latin America and the Caribbean alone, more than 248 million people have not yet had their first dose of Covid-19 vaccine, Etienne said during a press briefing. Countries with low vaccination rates likely will see future increases in illnesses, hospitalisations and deaths, she said.

“We are not yet out of this pandemic,” said Dr Ciro Ugarte, PAHO's director of health emergencies. “We still need to approach this pandemic with a lot of caution.”