Some fully vaccinated people who get infected with coronavirus develop long-term COVID-19 symptoms, a new study finds.
Israeli researchers looked at immunized healthcare workers, 19 percent of those who were infected despite their vaccinated status had symptoms for at least six weeks.
This was a small study, including only 39 breakthrough infections – seven of which led to long Covid.
Experts say that future research in this area should follow patients for longer than six weeks.
Still, the findings are troubling as the Indian ‘Delta’ variant spreads in the U.S. and globally. This study was conducted before Delta reached Israel – and breakthrough infections in the country are now much more common.
Vaccinated people can get long Covid from a breakthrough infection, a new study from Israel finds. Pictured: A woman receives a booster shot of the Pfizer vaccine at Sheba Medical Center near Tel Aviv, Israel
The Covid vaccines currently in use in the U.S. are very effective in protecting people against the coronavirus – especially against severe disease, hospitalization, and death.
This effectiveness has been demonstrated by countless studies, as well as the low numbers of Americans who have been hospitalized or died from Covid after full vaccination.
The Centers for Disease Control and Prevention (CDC) has identified just 5,914 such cases as of July 19 – out of more than 160 million Americans who are fully vaccinated.
But there’s much less data available on how well the vaccines protect against so-called ‘long Covid.’
In long Covid, patients suffer from prolonged symptoms such as brain fog, fatigue, and loss of smell. Some patients have been impacted for more than a year.
As more breakthrough infections are documented with the Delta variant sweeping across the world, long Covid patients and advocates have grown concerned that such infections may lead to more people getting this condition.
A new study from Israel suggests that long Covid is indeed possible when a patient is infected after vaccination.
The study was published Wednesday in the New England Journal of Medicine.
Researchers at the Sheba Medical Center in Ramat Gan, near Tel Aviv, tracked breakthrough infections among vaccinated healthcare workers.
This institution is the largest medical center in Israel. It employs more than 12,000 healthcare workers, 91 percent of whom received the Pfizer vaccine.
Between January and April 2021, the Israeli researchers evaluated healthcare workers with symptom questionnaires, contact tracing, and other measures to identify breakthrough cases.
Out of about 1,500 vaccinated healthcare workers who opted into the study, 39 had breakthrough infections.
That’s a rate of just 2.6 percent – much lower than the case rates in Israel overall at the time.
Most of these 39 healthcare workers with breakthrough cases had mild symptoms, in line with other findings on the vaccines’ protective abilities.
Most patients infected with Covid after vaccination have mild cases, but some can have symptoms in line with long Covid. Pictured: Hospital staff at a medical center in Tel Aviv, Israel
But a small number had more persistent symptoms.
About 31 percent of the patients still had symptoms after two weeks – and 19 percent still had symptoms after six weeks.
That 19 percent represents just seven patients out of the original group of 1,500. But was sufficient for the researchers to conclude that long-term Covid symptoms are possible after vaccination.
Among those patients with long Covid, the most common symptoms were prolonged loss of smell, cough, fatigue, and weakness.
One worker still hadn’t returned to work by the end of the six-week study period.
‘It’s really disturbing,’ Dr Gili Regev-Yochay, director of the infection, prevention and control unit with the Sheba Medical Center and an author of the study, told NPR.
‘If this is what we’re going to see with all of the even mildly symptomatic infections that we’re seeing now, it’s definitely worrisome,’ she said.
Patients who got sick with Covid after vaccination had slightly lower antibody levels, on average, compared to those who were vaccinated and did not get sick
The researchers also compared antibody levels and other immune system measures of the breakthrough case patients to measurements of vaccinated healthcare workers who did not become infected.
These measurements suggested that the breakthrough patients had slightly lower antibody levels than vaccinated patients who didn’t get infected – indicating that their immune systems were less prepared to face the virus.
Low neutralizing antibody levels may be a sign of potential breakthrough infection, the researchers said.
The study included a small number of long Covid patients and followed them for only six weeks – a short period, when the condition can last for a year or more.
Experts are calling for more research on this topic that may back up the Israeli study’s findings.
‘We need more research to see whether this happens at the same frequency as #LongCOVID in unvaccinated people, but it does confirm that Long COVID from breakthrough infections is possible,’ said Hannah Davis, a long COVID patient and researcher with the Patient-Led Research Collaborative, in a Twitter post sharing the study.
Even a small number of long Covid cases among vaccinated patients is cause for concern.
The Israeli study was done at a time that Alpha (or the UK variant, B.1.1.7) was dominant in Israel – and the researchers found that it was present in 85 percent of breakthrough cases.
Delta is more infections than Alpha and may be causing more breakthrough cases – amplifying long Covid worries.
‘We need a whole lot more data, but this is a really important first look in understanding the burden of breakthroughs,’ said Dr Katelyn Jetelina, author of the Your Local Epidemiologist newsletter, in a post commenting on the study.
‘We know that Delta is less forgiving than Alpha. If you’re not convinced already, it’s time to mask up.’