Many public health officials have taken heart in early evidence
that suggests infections from the omicron variant tend to cause less severe
illness than other versions of the coronavirus. But another important question
looms: whether infection with omicron, including breakthrough cases in
vaccinated people, can result in long
COVID — the constellation of physical,
neurological and cognitive symptoms that can last for months and impair
people’s daily lives.
اضافة اعلان
It is too early for scientists to know much about the
relationship between omicron, vaccination and long COVID. Research from earlier
in the pandemic does not yield definitive clues. Here is a sketch of what
scientists have learned and the many questions still to be answered.
How long might omicron symptoms persist?
Because the omicron variant was first identified in late
November, it is too early to say how long symptoms of infection can persist. It
is also unclear whether, like previous versions of the virus, it can lead to
the emergence of problems like brain fog or extreme fatigue after the infection
has resolved.
While recent reports suggest that omicron may cause less severe
initial illness than other variants, the basic symptoms of infection with
omicron are similar to infection with other variants, suggesting that long-term
effects could also be similar.
Milder initial illnesses do not necessarily mean that omicron is
less likely to lead to long COVID, doctors, researchers and patient-led groups
caution. Studies from earlier waves of the pandemic indicate that many people
who had mild or asymptomatic initial reactions to coronavirus infection went on
to develop long COVID that persisted for months.
Can vaccines prevent long COVID?
Maybe.
Vaccines primarily prevent people from getting seriously ill or
dying from a coronavirus infection. With some previous variants, vaccines
seemed to reduce the likelihood of infection itself — and not being infected
is, of course, the best way to avoid long COVID. But vaccines have not been as
effective in preventing infection with omicron, and breakthrough infections
with this new variant are far more common.
Studies looking at vaccinated people and long COVID have so far
mostly focused on data collected before the emergence of the delta variant. And
the study results have been mixed.
Can vaccines help if you already have long COVID?
When vaccines were first rolled out, before the emergence of the
more contagious delta variant which preceded the even-more-contagious omicron
variant, some patients with long COVID were finding that symptoms like brain
fog, joint pain, shortness of breath and fatigue improved after they were
vaccinated. Still, many people experienced no difference in their symptoms
after vaccination and a small percentage said they felt worse.
A study by the Office for National Statistics in Britain found
that in people ages 18-69 who reported their symptoms between February and
September 2021, a first dose of a vaccine lowered the odds of reporting long
COVID symptoms by 13%. A second dose further lowered the odds by 9%, the study
found.
Some researchers say it might make scientific sense that
vaccines could help some people with long COVID.
The cause of long COVID is still unclear, and different symptoms
might have different underlying causes in different patients, experts say. Some
leading theories are that the condition may be related to remnants of the virus
or its genetic material lingering after the initial infection subsides or to
inflammation or blood circulation problems spurred by an overactive immune
response that is unable to shut down.
Akiko Iwasaki, an immunologist at Yale, has said that vaccines
may be able to provide lasting relief in people whose symptoms are caused by
vestiges of the virus if the antibodies generated by the vaccines eliminate
those remnants. But in people whose symptoms may be caused by a post-viral
response resembling an autoimmune disease, she said, vaccines may help only
temporarily and problems like fatigue could reemerge.
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