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Friday, February 28, 2025

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

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1086 days ago
20220310
FILE - Dr. Joseph Ballinger giving Marjorie Hill, a nurse at Montefiore Hospital in New York, the first Asian flu vaccine shot to be administered in New York on Aug. 16, 1957. (AP Photo/File)

FILE - Dr. Joseph Ballinger giving Marjorie Hill, a nurse at Montefiore Hospital in New York, the first Asian flu vaccine shot to be administered in New York on Aug. 16, 1957. (AP Photo/File)

By MIKE STO­BBE | AS­SO­CI­AT­ED PRESS

 

NEW YORK (AP) — Two years in­to the COVID-19 pan­dem­ic, most of the world has seen a dra­mat­ic im­prove­ment in in­fec­tions, hos­pi­tal­iza­tions and death rates in re­cent weeks, sig­nalling 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.

About 65% of Amer­i­cans are ful­ly vac­ci­nat­ed, and about 29% are both vac­ci­nat­ed and boost­ed. Cas­es have been falling for near­ly two months, with the U.S. dai­ly av­er­age drop­ping about 40% in the last week alone. Hos­pi­tal­iza­tions al­so have plum­met­ed, down near­ly 30%. Mask man­dates are van­ish­ing — even fed­er­al health of­fi­cials have stopped wear­ing them — and Pres­i­dent Joe Biden has said it’s time for peo­ple to re­turn to of­fices and many as­pects of pre-pan­dem­ic life.

But this pan­dem­ic has been full of sur­pris­es, last­ing more than two years and caus­ing near­ly 1 mil­lion deaths in the U.S. and more than 6 mil­lion around the world. Its sever­i­ty has been sur­pris­ing, in part be­cause many peo­ple drew the wrong les­son from a 2009-2010 flu pan­dem­ic that turned out to be nowhere as dead­ly as ini­tial­ly feared.

“We got all wor­ried but then noth­ing hap­pened (in 2009), and I think that was what the ex­pec­ta­tion was” when COVID-19 first emerged, said Kristin Heit­man, a Mary­land-based re­searcher who col­lab­o­rat­ed with Char­ters.

That said, some ex­perts of­fered take­aways from past epi­demics that may in­form how the end of the COVID-19 pan­dem­ic may play out.

FILE - A woman receives a COVID-19 vaccine injection by a pharmacist at a clinic in Lawrence, Mass., on Wednesday, Dec. 29, 2021. One of the first studies to look at the performance of COVID-19 booster shots during the recent omicron wave of illnesses found a surprising decline in effectiveness after only four months. The findings are based on data from hospitals and urgent care centers in 10 states. (AP Photo/Charles Krupa, File)

FILE - A woman receives a COVID-19 vaccine injection by a pharmacist at a clinic in Lawrence, Mass., on Wednesday, Dec. 29, 2021. One of the first studies to look at the performance of COVID-19 booster shots during the recent omicron wave of illnesses found a surprising decline in effectiveness after only four months. The findings are based on data from hospitals and urgent care centers in 10 states. (AP Photo/Charles Krupa, File)

 

FLU

 

Be­fore COVID-19, in­fluen­za was con­sid­ered the most dead­ly pan­dem­ic agent. A 1918-1919 flu pan­dem­ic killed 50 mil­lion peo­ple around the world, in­clud­ing 675,000 in the U.S., his­to­ri­ans es­ti­mate. An­oth­er flu pan­dem­ic in 1957-1958 killed an es­ti­mat­ed 116,000 Amer­i­cans, and an­oth­er in 1968 killed 100,000 more.

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 U.S. deaths were at­trib­uted to that pan­dem­ic.

The World Health Or­ga­ni­za­tion 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.”

FILE - People visit the 21,000 panel Names Project AIDS Memorial Quilt in Washington on Saturday, Oct. 10, 1992. The Washington Monument is seen in the background. (AP Photo/Shayna Brennan, File)

FILE - People visit the 21,000 panel Names Project AIDS Memorial Quilt in Washington on Saturday, Oct. 10, 1992. The Washington Monument is seen in the background. (AP Photo/Shayna Brennan, File)

 

HIV

 

In 1981, U.S. 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.

Re­searchers lat­er de­ter­mined it was caused by HIV — hu­man im­mun­od­e­fi­cien­cy virus — which weak­ens a per­son’s im­mune sys­tem by de­stroy­ing cells that fight dis­ease and in­fec­tion. For years, AIDS was con­sid­ered a ter­ri­fy­ing death sen­tence, and in 1994 it be­came the lead­ing cause of death for Amer­i­cans ages 25 to 44.

But 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.

FILE - Angelica Pereira, left, holds her daughter Luiza, who was born with microcephaly because of the Zika virus, as she sits with her husband Dejailson Arruda, at their home in Santa Cruz do Capibaribe, Pernambuco state, Brazil on Dec. 23, 2015. (AP Photo/Felipe Dana, File, File)

FILE - Angelica Pereira, left, holds her daughter Luiza, who was born with microcephaly because of the Zika virus, as she sits with her husband Dejailson Arruda, at their home in Santa Cruz do Capibaribe, Pernambuco state, Brazil on Dec. 23, 2015. (AP Photo/Felipe Dana, File, File)

 

ZI­KA

 

In 2015, Brazil suf­fered an out­break of in­fec­tions from Zi­ka virus, spread by mos­qui­toes that tend­ed to cause on­ly mild ill­ness in most adults and chil­dren. But it be­came a ter­ror as it emerged that in­fec­tion dur­ing preg­nan­cy could cause a birth de­fect that af­fect­ed brain de­vel­op­ment, caus­ing ba­bies to be born with un­usu­al­ly small heads.

By late that year, mos­qui­toes were spread­ing it in oth­er Latin Amer­i­can coun­tries, too. In 2016, the WHO de­clared it an in­ter­na­tion­al pub­lic health emer­gency, and a U.S. im­pact be­came clear. The Cen­ters for Dis­ease Con­trol and Pre­ven­tion re­ceived re­ports of 224 cas­es of Zi­ka trans­mis­sion by mos­qui­toes in the con­ti­nen­tal Unit­ed States and more than 36,000 in U.S. ter­ri­to­ries — the vast ma­jor­i­ty in Puer­to Ri­co.

But the counts fell dra­mat­i­cal­ly in 2017 and vir­tu­al­ly dis­ap­peared short­ly af­ter, at least in the U.S. Ex­perts be­lieve the epi­dem­ic died as peo­ple de­vel­oped im­mu­ni­ty. “It just sort of burned out” and the pres­sure for mak­ing a Zi­ka vac­cine avail­able in the U.S. ebbed, said Dr. Denise Jamieson, a for­mer CDC of­fi­cial who was a key leader in the agency’s re­spons­es to Zi­ka.

It’s pos­si­ble Zi­ka will be a dor­mant prob­lem for years, but out­breaks could oc­cur again if the virus mu­tates or if larg­er num­bers of young peo­ple come along with­out im­mu­ni­ty. With most epi­demics, “there’s nev­er a hard end,” said Jamieson, who is now chair of gy­nae­col­o­gy and ob­stet­rics at Emory Uni­ver­si­ty’s med­ical school.

FILE - Health workers wearing protective suits tend to an Ebola victim kept in an isolation tent in Beni, Democratic Republic of Congo, on Saturday, July 13, 2019. (AP Photo/Jerome Delay, File)

FILE - Health workers wearing protective suits tend to an Ebola victim kept in an isolation tent in Beni, Democratic Republic of Congo, on Saturday, July 13, 2019. (AP Photo/Jerome Delay, File)

 

COVID-19

 

The Gene­va-based WHO de­clared COVID-19 a pan­dem­ic on March 11, 2020, and it will de­cide when enough coun­tries have seen a suf­fi­cient de­cline in cas­es — or, at least, in hos­pi­tal­iza­tions 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 U.S. and dropped glob­al­ly in the last week by 5%. But cas­es are ris­ing in some places, in­clud­ing the Unit­ed King­dom, 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 with re­porters. Coun­tries with low vac­ci­na­tion rates like­ly will see fu­ture in­creas­es in ill­ness­es, hos­pi­tal­iza­tions, 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.”

COVID-19Health


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