Ex­perts say North­ern Hemi­sphere coun­tries face an un­pre­dictable win­ter as COVID con­tin­ues to spread dur­ing the flu sea­son.

By Eliz­a­beth Me­limopou­los – Al­jazeera

Coun­tries in the North­ern Hemi­sphere are fac­ing an un­pre­dictable win­ter as COVID-19 con­tin­ues to spread dur­ing the flu sea­son, ex­perts have warned.

Last year, when gov­ern­ments rec­om­mend­ed a range of pro­tec­tive mea­sures such as mask-wear­ing, so­cial dis­tanc­ing and lock­downs to slow COVID-19 in­fec­tions, the num­ber of in­fluen­za cas­es dropped dra­mat­i­cal­ly com­pared with the sea­son­al av­er­age.

Ac­cord­ing to the Eu­ro­pean Cen­tre for Dis­ease Pre­ven­tion and Con­trol (ECDC) about 20 per­cent of the pop­u­la­tion catch­es the flu each year, but that fig­ure fell by more than 99 per­cent in 2020-21. There were no hos­pi­talised cas­es nor fa­tal­i­ties re­port­ed from in­fluen­za last sea­son.

Cas­es this year have re­mained low, ac­cord­ing to the World Health Or­ga­ni­za­tion (WHO), but with COVID re­stric­tions be­ing lift­ed in many parts of the world, chil­dren back in school, and the coro­n­avirus con­tin­u­ing to spread, ex­perts are urg­ing peo­ple to re­main cau­tious. An uptick of in­fluen­za cas­es could bur­den health sys­tems al­ready fac­ing dif­fi­cul­ties due to out­breaks of COVID-19.

What is in­fluen­za, and when does the sea­son for it start (North and South)?

In­fluen­za (flu) is a con­ta­gious res­pi­ra­to­ry ill­ness caused by in­fluen­za virus­es that cir­cu­late around the world and are typ­i­cal­ly more preva­lent when it is cold.

Ac­cord­ing to the Unit­ed States Cen­ters for Dis­ease Con­trol and Pre­ven­tion (CDC), there are four types of in­fluen­za virus­es A, B, C and D.

But “hu­man in­fluen­za A and B virus­es cause sea­son­al epi­demics of dis­ease known as flu sea­son.”

Peo­ple with in­fluen­za of­ten show symp­toms like fever, cough, mus­cle and joint pain, headache, run­ny nose and sore throat. Gen­er­al­ly, peo­ple re­cov­er from these symp­toms with­out re­quir­ing med­ical at­ten­tion, but the virus can al­so cause se­vere ill­ness or death, es­pe­cial­ly in high-risk pop­u­la­tions.

Ac­cord­ing to the WHO, an­nu­al in­fluen­za epi­demics are re­spon­si­ble for about three to five mil­lion cas­es of se­vere ill­ness, and about 290,000 to 650000 res­pi­ra­to­ry deaths.

Dur­ing peak sea­sons an in­fluen­za epi­dem­ic can over­whelm health sys­tems. In the North­ern Hemi­sphere, the sea­son can start in Oc­to­ber and last un­til April or May. In the South­ern Hemi­sphere, the sea­son can run from April-Sep­tem­ber.

Could this sea­son be hard­er than oth­ers?

Ex­perts have said it is dif­fi­cult to pre­dict the sever­i­ty of the flu sea­son in the North­ern Hemi­sphere, but some have warned it could be chal­leng­ing this year.

Last year, in­fluen­za ac­tiv­i­ty was dra­mat­i­cal­ly low­er com­pared with the pre­vi­ous years in both the South­ern and North­ern Hemi­spheres.

Due to the far low­er num­ber of in­fec­tions last year, the strains cir­cu­lat­ing this year may be hard­er for peo­ple’s im­mune sys­tems to de­tect, which could leave peo­ple more sus­cep­ti­ble to in­fec­tion and may even lead to more se­vere ill­ness.

“Nat­ur­al im­mu­ni­ty wanes, so with lit­tle in­fluen­za last year, peo­ple are more sus­cep­ti­ble,” Dr Robert Klug­man, med­ical di­rec­tor of em­ploy­ee health at UMass Memo­r­i­al Health in Worces­ter told Al Jazeera.

Dr Amesh Adal­ja, se­nior schol­ar at the Johns Hop­kins Cen­ter for Health Se­cu­ri­ty, said peo­ple con­tin­ue to take pre­cau­tions against catch­ing or trans­mit­ting COVID-19, which could lead to a milder flu sea­son com­pared with those be­fore the COVID pan­dem­ic.

“A lot of the peo­ple are still do­ing some of the mit­i­ga­tion mea­sures from COVID-19 that had an im­pact on flu, like so­cial dis­tanc­ing, wear­ing masks, be­ing care­ful when they are in a high-risk set­ting,” said Dr Adal­ja.

“So I do think that flu is go­ing to be more com­mon this sea­son in the North­ern Hemi­sphere than it was last sea­son, but I think it might be a milder sea­son than the ones we had in the pre-COVID era,” he added.

Ex­perts al­so warned that an in­crease in flu cas­es could over­whelm health sys­tems in coun­tries where COVID-19 hos­pi­tal­i­sa­tions are high.

“We have a pro­por­tion of peo­ple that are still sus­cep­ti­ble to COVID-19 in­fec­tions due to im­mune prob­lems and not be­ing vac­ci­nat­ed,” Dr Ly­no­ra Saxinger, an in­fec­tious-dis­ease ex­pert at the Uni­ver­si­ty of Al­ber­ta, said.

“That could eas­i­ly over­whelm our health care sys­tem and if we just add that lay­er of in­fluen­za on top of that, it would be a high-risk sce­nario.”

Ac­cord­ing to Dr Saxinger the in­fluen­za sea­son or­di­nar­i­ly “re­sults in health care sys­tems strained”.

Can we get the flu and the COVID-19 vac­cines at the same time?

A re­port re­leased by the Lancet in No­vem­ber said it is safe to ad­min­is­ter both vac­cines at the same time, not­ing that giv­ing both shots in one sit­ting “could re­duce the bur­den on health-care sys­tems”.

“It is quite rou­tine to get mul­ti­ple vac­cines at the same time,” Dr Saxinger said. “I think that is a re­al op­por­tu­ni­ty, be­cause peo­ple are much more like­ly to com­ply or take the sec­ond vac­cine if it can be done in the same vis­it.”

Re­gard­ing the side ef­fects, Dr Saxinger said some peo­ple have al­most none and oth­ers have some symp­toms re­lat­ed to “an im­mune re­sponse.”

The CDC al­so not­ed that both vac­cines can be “giv­en at the same time”, while adding that side ef­fects are “gen­er­al­ly sim­i­lar whether vac­cines are giv­en alone or with oth­er vac­cines”.

How can we mit­i­gate risks?

Ex­perts have said that much of the health guid­ance that has been in­tro­duced dur­ing the pan­dem­ic can help to mit­i­gate the risk of spread­ing the flu.

Ac­cord­ing to the CDC, the health mea­sures that help to pro­tect against the flu are: avoid close con­tact with peo­ple who are sick, stay home when sick, wash hands reg­u­lar­ly, avoid touch­ing the eyes, nose or mouth, and cov­er the mouth and nose.

“The mea­sures against COVID worked ex­cel­lent­ly against in­fluen­za,” Dr Saxinger said. “I ac­tu­al­ly think that if peo­ple keep up the use of masks, [and] are ju­di­cious about their in­ter­ac­tions, it would make a huge dif­fer­ence.”

Dr Ri­car­do So­to-Ri­fo of the Uni­ver­si­ty of Chile’s In­sti­tute of Bio­med­ical Sci­ences, al­so high­light­ed the use of masks.

“The face masks act as a bar­ri­er,” Dr So­to-Ri­fo said. “And it works both ways, they pro­tect you from spread­ing the virus, but al­so they keep the virus out,” he added.

“There are dif­fer­ent types of masks some bet­ter than oth­ers in terms of the pro­tec­tion they pro­vide, but they def­i­nite­ly help and make a dif­fer­ence.”

What lessons can the north learn from the South­ern Hemi­sphere?

Ac­cord­ing to the WHO, the in­fluen­za sea­son in the South­ern Hemi­sphere this year was sim­i­lar to the pre­vi­ous year. In a re­port re­leased in Sep­tem­ber, the or­gan­i­sa­tion said that in Aus­tralia, the health au­thor­i­ties re­port­ed “in­fluen­za-like ill­ness ac­tiv­i­ty re­mained at his­tor­i­cal­ly low lev­els.”

The WHO said that sim­i­lar trends were al­so ob­served in Chile “where sen­tinel hos­pi­tal da­ta show in­fluen­za ac­tiv­i­ty falling to near­ly ze­ro in the spring of 2020 and large­ly re­main­ing there through­out 2020 and 2021.”

Dr So­to-Ri­fo said that dif­fer­ent vari­ables could ex­plain the low rates of flu.

“In Chile, the vac­ci­na­tion cam­paign start­ed hav­ing an ef­fect, there were al­so mo­bil­i­ty mea­sures well es­tab­lished, and the use of masks was manda­to­ry,” So­to-Ri­fo said.

“So, we saw how the num­bers of deaths and hos­pi­tal oc­cu­pa­tion dra­mat­i­cal­ly dropped,” he added.

How­ev­er, as sum­mer starts in the South­ern Hemi­sphere, and some mea­sures are re­laxed, Dr So­to-Ri­fo said there are con­cerns that COVID-19 cas­es con­cerns could grow.

“Last sum­mer, we saw a dra­mat­ic in­crease of cas­es, so it’s still very un­cer­tain what fol­lows next,” he added.

Ac­cord­ing to Dr So­to-Ri­fo one chal­lenge that Chile did ob­serve dur­ing its win­ter was the rise of rates of res­pi­ra­to­ry syn­cy­tial virus (RSV) in chil­dren – this is a com­mon virus that typ­i­cal­ly in­fects young peo­ple and can some­times cause pneu­mo­nia.

“Chil­dren are good vec­tors of res­pi­ra­to­ry virus­es, but keep­ing the mea­sures in place helped,” So­to-Ri­fo said.

“I think the most im­por­tant thing that we should not for­get is that we are still in a pan­dem­ic, and as tir­ing as it might be, we need to keep the health mea­sures in place.”