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March 17, 2021

How do vaccines affect Covid-19 long-haulers? Here's what the evidence says so far.

Daily Briefing

    Covid-19 long-haulers are reporting that their symptoms have eased after getting vaccinated, but the science on whether Covid-19 vaccines can alleviate symptoms is still out.

    New toolkit: Covid-19 vaccine communications readiness assessment

    Covid-19 long-haulers report improvement in their symptoms following vaccination

    According to the World Health Organization, patients with Covid-19 typically recover from the disease in about two weeks' time, but there are a number of patients who have had Covid-19 symptoms for months.

    U.S. clinicians and researchers do not yet know how many people have experienced lingering symptoms or what their symptoms might be, the Washington Post reports. In December 2020, NIH held a workshop to begin to address those questions and suggested 10% to 30% of Covid-19 patients experience long-term symptoms. But now, new questions are emerging as Covid-19 long haulers are reporting improvements in their symptoms after getting vaccinated.

    For example, Mara Gay, a member of the New York Times' editorial board, in a tweet last month wrote that she felt "significantly better" after she received her first vaccine dose.

    Similarly, Sharon MacMillan, an OB-GYN in Massachusetts, in tweet last month wrote that a lingering "dull headache behind [her] right eye … went away" after her first vaccine dose and hasn't returned.

    And Arianna Eisenberg, who had experienced Covid-19 symptoms—including brain fog, fatigue, insomnia, and muscle pain—for eight months, said her symptoms disappeared 36 hours after she received her second dose of a Covid-19 vaccine last month and haven't come back since then.

    What we don't know yet

    The reports are prompting researchers to ask a new set of questions, including: Are Covid-19 long-haulers experiencing a placebo effect from Covid-19 vaccines? Why would vaccines, which stimulate the immune system, help long-haulers if their immune systems have never reset?

    "The only thing that we can safely assume is that an unknown proportion of people who acquire [the novel coronavirus] have long-term symptoms," said Steven Deeks, an infectious-disease physician at the University of California-San Francisco. "We know the questions. We have no answers. Hard stop."

    Although there's no conclusive research on whether Covid-19 vaccines alleviate long-term Covid-19 symptoms, some new research is beginning to shed light on question.

    For example, a preprint study published Monday on medRxiv found long-haulers who've been vaccinated are more likely to see their symptoms resolve or not worsen than people with lingering symptoms who haven't been vaccinated. But the study, which has not yet been peer reviewed, relied on a small sample size, comparing only 44 vaccinated patients against 22 unvaccinated patients to determine whether Covid-19 vaccines are safe for long-haulers. According the study's authors, it's possible the vaccine affected patients' recall of symptoms, which they described as "a placebo/nocebo effect."

    In addition, an informal survey conducted by Survivor Corps, an online organization for people with long-term Covid-19 symptoms, showed 216 people said they felt no different after getting vaccinated, 171 said their symptoms had improved, and 63 reported feeling worse, according to Diana Berrent, the organization's founders.

    Another informal survey of Covid-19 patients with long-term symptoms from several Facebook groups and the Body Politic Slack group, an organization tracking Covid-19 long-haulers, found long-haulers reported improvements in their symptoms after getting vaccinated. A total of 473 long-haulers responded to the survey. Among the respondents, 80% were from the United Kingdom and 15% from the United States. The majority of respondents received Pfizer/BioNTech's vaccine (60%), followed by AstraZeneca (30%), and Moderna (9%).

    According to that survey, 9% of patients reported that their symptoms improved after their first vaccine dose, and after two weeks, 16% said they felt much better. Among respondents who had their vaccine two weeks ago or longer, 27% said their long-term Covid-19 symptoms had slightly improved, while only 14% said their symptoms were slightly worse. In addition, the survey showed about 5% of respondents felt completely back to normal, and only 3.8% of respondents felt much worse than previously.

    Akiko Iwasaki, an immunologist at Yale University, said vaccinations are likely to reduce people's chances of experiencing long-term Covid-19 symptoms based on evidence showing vaccines help prevent Covid-19. "Vaccines will generate good antibody and T-cell responses. They have been already shown to significantly reduce infection, both symptomatic and asymptomatic," she said.

    In a blog post for Elemental, Iwasaki outlined three reasons why Covid-19 vaccines might improve long-haulers' symptoms: T cells that were boosted by the vaccine could eliminate a viral reservoir, heightened immune responses could clear virus fragments, or the vaccine may "divert autoimmune cells" if long-term symptoms stem from an inappropriate autoimmune response.

    Similarly, Deeks said Covid-19 vaccines could be triggering an immune response adequate enough to eliminate reservoirs of the coronavirus hiding inside the bodies of people with lingering symptoms.

    For now, researchers are continuing to investigate whether vaccines improve the symptoms of long-haulers. NIH, for example, announced it will spend more than $1.1 billion over four years to study the effects of long-term Covid-19 (Bernstein/Guarino, Washington Post, 3/16; Fernandez, Axios, 3/17; Fiore, MedPage Today, 3/4).

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