Third dose of Covid vaccine can raise antibody levels by as much 687-fold in organ transplant recipients who had almost no virus-fighting immune cells after two shots, study finds
- Third dose of vaccine led to high antibody response in transplant recipients who previously had low antibody responses
- About 10% of people with negative antibody responses developed a high antibody response as well
- Transplant recipients are less likely to develop a high antibody response than people on dialysis
- Third booster dose may be needed in coming months as variants of virus spread
A third dose of COVID-19 vaccines could be more effective for organ transplant recipients than the first two doses, a new study finds.
Researchers from Johns Hopkins University looked at organ transplant recipients and found that patients who had low antibody levels after the first two doses saw an increase after the third dose.
The biggest increase seen were antibody levels that rose 687-fold.
They also found that one-third of patients who developed negative antibody levels – meaning they did not have any immune-fighting cells – from the first two doses now showed an increase in antibody levels.
Researchers believe that this could mean the third dose is more effective than the previous two for some individuals, though they can not be certain yet.
While the COVID vaccine is deemed to be effective in the general population, not all people are seeing the same results while using it.
A recent study found that organ transplant recipients are more likely to develop high anti-body responses from the third dose of a COVID vaccine than from the previous two
For the study, published in the Annals of Internal Medicine on Monday, looked at 30 patients who had undergone heart, kidney, liver, lung or pancreas transplants.
Some had had transplants as recently as one year ago and other as late as 18 years ago.
The patients all had two shots of the Pfizer-BioNTech and Moderna vaccine and received a third dose of the those vaccines or the Johnson & Johnson jab.
All six patients in the study who had reported low antibody levels reported high antibody levels two weeks after receiving the third dose of the vaccine.
Of the 24 patients with negative antibody reactions, six developed high antibody responses, two developed low antibody responses and the remaining 16 still had negative antibody responses.
‘Additional vaccine doses (with the same, or a different vaccine) may provide the immune system with another opportunity to “see” and respond to the virus protein in the vaccine,’ Dr William Werbel, lead author of the study and a fellow at Johns Hopkins, said of why the third shot may be more effective.
‘This may be required for certain transplant patients with sluggish immune responses to foreign proteins – a consequence of the daily medications they take to suppress the immune system – to be able to boost low-level immune memory up to detectable, and ideally protective levels of antibody.
‘This strategy has been employed for other viruses such as influenza and hepatitis B.’
A study from last week found that kidney transplant patients who were using immunosuppressant therapy were less likely to develop antibodies after receiving both doses of the vaccine – at only 18 percent.
People who had instead been using dialysis to treat their kidney conditions were 90 percent likely to develop antibodies.
Whether or not the level of antibodies truly matters is yet to be determined, though, as researchers are not certain if there is a threshold for immunity.
There have been cases of vaccinated transplant patients with low antibody level contractive the virus, though.
Researchers believe that the third dose of a vaccine, which is often a booster shot meant to protect people from variants of COVID-19, could be incorporated into the treatment regiment of transplant recipients in order to protect them.
They would need further research to be done of transplant recipients and the booster shot first, though.
The authors still recommend that, despite these results, the standard series of shots should still be used in all patients.
‘Given the excellent safety and effectiveness of the standard COVID-19 vaccine series in the general population, these series continue to be, and should remain recommended by all governmental organizations and transplant societies,’ Werbel said.
The effectiveness of vaccines has also been put into doubt with cancer patients, as a study from last month found that one in ten cancer patients where producing low antibody responses to the vaccine.
A third dose of the COVID vaccines may be needed soon to further protect Americans from the variants of the virus forming across the globe.
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