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NIH begins study looking at effects of a COVID-19 booster shot in kidney transplant recipients

The National Institutes of Health (NIH) has launched a study investigating the impacts of third COVID-19 vaccine doses in kidney transplant recipients.

The study will include up to 200 adults who received a kidney transplant at least a year ago and who failed to develop antibodies against the virus after two vaccine doses.

Preliminary results for the trial are expected in September 2021, and these results will help inform the federal government’s decision on whether or not to authorize third doses for use in the U.S.

While U.S. public health agencies do not currently recommend booster shots for the general population, kidney transplant recipients and other Americans with weakened immune systems may require a third dose to adequately protect them against Covid.

Studies have shown that organ transplant recipients are unlikely to be well-protected against Covid after two-shot vaccination. Pictured: A Thai medical official prepares a booster shot

Additional COVID-19 vaccine shots – also called boosters – are a contentious issue in the U.S.

Both Pfizer and Moderna have said that third doses will soon be needed to protect people against the Indian ‘Delta’ variant, citing data showing that immunity from a two-dose regimen wanes after several months.

Meanwhile, the World Health Organization (WHO) and other public health experts have said booster shots are currently unnecessary and that vaccinating people living in low-income countries should be a priority instead.

But there’s growing evidence that booster shots are necessary for one specific group of patients: those whose immune systems have been weakened by disease or treatment.

These immunocompromised people make up about three percent of the U.S. population. They include recipients of organ transplants, cancer patients, and others.

With weakened immune systems, these patients are both less likely to see robust protection from a typical vaccine regimen and are more vulnerable to Covid itself.

‘It is extremely important for us to move to get those individuals their boosters,’ Dr. Anthony Fauci said last week, ‘and we are now working on that and will make that be implemented as quickly as possible, because for us and, for the individuals involved, it is a very high priority.’ 

Fauci is the director of the National Institute of Allergy and Infectious Diseases (NIAID), a branch of NIH that is now investigating how well booster shots work in kidney transplant recipients, the agency announced Tuesday.

Organ transplant recipients are immunocompromised because, as part of the transplant process, they must take drugs that prevent the body from fighting against a new organ.

These drugs lower the immune system’s response to foreign cells, including both the new organ and future infections, like Covid.

While not recommending booster shots for everyone, Dr. Fauci says that immunocompromised Americans need additional protection against Covid

While not recommending booster shots for everyone, Dr. Fauci says that immunocompromised Americans need additional protection against Covid

Past studies have shown that organ transplant recipients are especially unlikely to develop antibody responses to Covid after vaccination.

One June 2021 study found that just 18 percent of kidney transplant recipients developed this response.

As a result, the NIH seeks to understand whether a third dose of a Pfizer or Moderna vaccine can sufficiently boost the immune system to provide these vulnerable patients with protection.

The study also plans to identify any specific factors that would make kidney transplant recipients better-positioned to benefit from a third dose.

This trial will enroll up to 200 adults who received a kidney transplant at least one year ago, the NIH says.

Researchers are aiming to enroll 50 to 100 participants who did not build up any Covid antibodies after two doses of Pfizer or Moderna vaccination, as well as 50 to 100 participants who built some antibodies – but not enough to provide significant protection.

All participants will receive a third dose of the same vaccine that they previously received.

Then, 30 days later, NIH researchers will measure their antibody responses.

The agency intends to publish initial results from those antibody measures in September 2021.

These data will inform decision-making on whether federal agencies authorize a three-dose vaccine regimen for use in the U.S.

Patients will continue to be part of the trial for a year, however, so the NIH can follow up on their protection against Covid. 

Though this third dose is likely to boost patients’ immunity, the NIH is careful not to refer to this trial as a ‘booster shot’ study.

Instead, the agency notes that a third dose could bring kidney transplant recipients up to the same immunity level as those who receive two doses and aren’t immunocompromised.

Similarly, a San Francisco hospital offering additional doses to Johnson & Johnson vaccine recipients is calling those shots ‘supplemental,’ since the J&J shot has lower protective abilities compared to Pfizer and Moderna.

  • In order to enroll, potential patients should contact Johns Hopkins University using the email address [email protected]


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