By MIKE STO­BBE | AS­SO­CI­AT­ED PRESS

NEW YORK (AP) — U.S. health of­fi­cials on Mon­day cut iso­la­tion re­stric­tions for asymp­to­matic Amer­i­cans who catch the coro­n­avirus from 10 to five days, and sim­i­lar­ly short­ened the time that close con­tacts need to quar­an­tine.

Cen­ters for Dis­ease Con­trol and Pre­ven­tion of­fi­cials said the guid­ance is in keep­ing with grow­ing ev­i­dence that peo­ple with the coro­n­avirus are most in­fec­tious in the two days be­fore and three days af­ter symp­toms de­vel­op.

The de­ci­sion al­so was dri­ven by a re­cent surge in COVID-19 cas­es, pro­pelled by the omi­cron vari­ant.

Ear­ly re­search sug­gests omi­cron may cause milder ill­ness­es than ear­li­er ver­sions of the coro­n­avirus. But the sheer num­ber of peo­ple be­com­ing in­fect­ed — and there­fore hav­ing to iso­late or quar­an­tine — threat­ens to crush the abil­i­ty of hos­pi­tals, air­lines and oth­er busi­ness­es to stay open, ex­perts say.

CDC Di­rec­tor Rochelle Walen­sky said the coun­try is about to see a lot of omi­cron cas­es.

“Not all of those cas­es are go­ing to be se­vere. In fact many are go­ing to be asymp­to­matic,” she told The As­so­ci­at­ed Press on Mon­day. “We want to make sure there is a mech­a­nism by which we can safe­ly con­tin­ue to keep so­ci­ety func­tion­ing while fol­low­ing the sci­ence.”

Last week, the agency loos­ened rules that pre­vi­ous­ly called on health care work­ers to stay out of work for 10 days if they test pos­i­tive. The new rec­om­men­da­tions said work­ers could go back to work af­ter sev­en days if they test neg­a­tive and don’t have symp­toms. And the agency said iso­la­tion time could be cut to five days, or even few­er, if there are se­vere staffing short­ages.

Now, the CDC is chang­ing the iso­la­tion and quar­an­tine guid­ance for the gen­er­al pub­lic to be even less strin­gent.

The change is aimed at peo­ple who are not ex­pe­ri­enc­ing symp­toms. Peo­ple with symp­toms dur­ing iso­la­tion, or who de­vel­op symp­toms dur­ing quar­an­tine, are en­cour­aged to stay home.

The CDC’s iso­la­tion and quar­an­tine guid­ance has con­fused the pub­lic, and the new rec­om­men­da­tions are “hap­pen­ing at a time when more peo­ple are test­ing pos­i­tive for the first time and look­ing for guid­ance,” said Lind­say Wi­ley, an Amer­i­can Uni­ver­si­ty pub­lic health law ex­pert.

Nev­er­the­less, the guid­ance con­tin­ues to be com­plex.

Iso­la­tion

The iso­la­tion rules are for peo­ple who are in­fect­ed. They are the same for peo­ple who are un­vac­ci­nat­ed, part­ly vac­ci­nat­ed, ful­ly vac­ci­nat­ed or boost­ed.

They say:

—The clock starts the day you test pos­i­tive.

—An in­fect­ed per­son should go in­to iso­la­tion for five days, in­stead of the pre­vi­ous­ly rec­om­mend­ed 10.

—At the end of five days, if you have no symp­toms, you can re­turn to nor­mal ac­tiv­i­ties but must wear a mask every­where — even at home around oth­ers — for at least five more days.

—If you still have symp­toms af­ter iso­lat­ing for five days, stay home un­til you feel bet­ter and then start your five days of wear­ing a mask at all times.

Quar­an­tine

The quar­an­tine rules are for peo­ple who were in close con­tact with an in­fect­ed per­son but not in­fect­ed them­selves.

For quar­an­tine, the clock starts the day some­one is alert­ed they may have been ex­posed to the virus.

Pre­vi­ous­ly, the CDC said peo­ple who were not ful­ly vac­ci­nat­ed and who came in close con­tact with an in­fect­ed per­son should stay home for at least 10 days.

Now the agency is say­ing on­ly peo­ple who got boost­er shots can skip quar­an­tine if they wear masks in all set­tings for at least 10 days.

That’s a change. Pre­vi­ous­ly, peo­ple who were ful­ly vac­ci­nat­ed — which the CDC has de­fined as hav­ing two dos­es of the Pfiz­er or Mod­er­na vac­cines, or one dose of the John­son & John­son vac­cine — could be ex­empt from quar­an­tine.

Now, peo­ple who got their ini­tial shots but not boost­ers are in the same sit­u­a­tion as those who are part­ly vac­ci­nat­ed or are not vac­ci­nat­ed at all: They can stop quar­an­tine af­ter five days if they wear masks in all set­tings for five days af­ter­ward.

Five Days

Sus­pend­ing both iso­la­tion and quar­an­tine af­ter five days is not with­out risk.

A lot of peo­ple get test­ed when they first feel symp­toms, but many Amer­i­cans get test­ed for oth­ers rea­sons, like to see if they can vis­it fam­i­ly or for work. That means a pos­i­tive test re­sult may not re­veal ex­act­ly when a per­son was in­fect­ed or give a clear pic­ture of when they are most con­ta­gious, ex­perts say.

When peo­ple get in­fect­ed, the risk of spread drops sub­stan­tial­ly af­ter five days, but it does not dis­ap­pear for every­one, said Dr. Aaron Glatt, a New York physi­cian who is a spokesman for the In­fec­tious Dis­eases So­ci­ety of Amer­i­ca.

“If you de­crease it to five days, you’re still go­ing to have a small but sig­nif­i­cant num­ber of peo­ple who are con­ta­gious,” he said.

That’s why wear­ing masks is a crit­i­cal part of the CDC guid­ance, Walen­sky said.

Vary­ing Rec­om­men­da­tions

The new CDC guid­ance is not a man­date; it’s a rec­om­men­da­tion to em­ploy­ers and state and lo­cal of­fi­cials. Last week, New York state said it would ex­pand on the CDC’s guid­ance for health care work­ers to in­clude em­ploy­ees who have oth­er crit­i­cal jobs that are fac­ing a se­vere staffing short­age.

It’s pos­si­ble oth­er states will seek to short­en their iso­la­tion and quar­an­tine poli­cies, and CDC is try­ing to get out ahead of the shift. “It would be help­ful to have uni­form CDC guid­ance” that oth­ers could draw from, rather than a mish­mash of poli­cies, Walen­sky said.

Giv­en the tim­ing with surg­ing case counts, the up­date “is go­ing to be per­ceived as com­ing in re­sponse to pres­sure from busi­ness in­ter­ests,” Wi­ley said. But some ex­perts have been call­ing for the change for months, be­cause short­er iso­la­tion and quar­an­tine pe­ri­ods ap­peared to be suf­fi­cient to slow the spread, she said.

The move by CDC fol­lows a de­ci­sion last week by U.K. of­fi­cials to re­duce the self-iso­la­tion pe­ri­od for vac­ci­nat­ed peo­ple who test pos­i­tive for COVID-19.