This is a follow-up study to an earlier one published in
March in JAMA, in which the researchers reported that only 17% of the
participating transplant recipients produced sufficient antibodies after just
one dose of a two-dose Covid-19 vaccine regimen.
Researchers have found that although two doses
of a vaccine against SARS-CoV-2 confers some protection for people who have
received solid organ transplants, it’s still not enough to enable them to
dispense with Covid safety measures.
In a study published in JAMA, Johns Hopkins Medicine researchers have
concluded that although two doses of a
coronavirus vaccine
confers some protection for people who have received solid organ transplants,
it’s still not enough to enable them to dispense with masks, physical
distancing and other safety measures.
This is a follow-up study to an earlier one published in March in
JAMA, in which the researchers reported that only 17% of the participating
transplant recipients produced sufficient antibodies after just one dose of a
two-dose
Covid-19 vaccine
regimen.
“While there was an increase
in those with detectable antibodies — 54% overall — after the second shot, the
number of transplant recipients in our second study whose antibody levels
reached high enough levels to ward off a SARS-CoV-2 infection was still well
below what’s typically seen in people with healthy immune systems. Based on our
findings, we recommend that transplant recipients and other immunocompromised
patients continue to practice strict COVID-19 safety precautions, even after
vaccination,” lead author Brian Boyarsky is quoted as saying on the Johns
Hopkins website.
People who receive solid organ transplants (such as heart, lungs and
kidneys) often must take drugs to suppress their immune systems and prevent
rejection. Such regimens may interfere with a transplant recipient’s ability to
make antibodies to foreign substances, including the protective ones produced
in response to vaccines.
The new study evaluated this immunogenic response following the
second dose of either the Moderna or Pfizer-BioNTech vaccine for 658 transplant
recipients, none of whom had a prior diagnosis of Covid-19. The participants
completed their two-dose regimen between December 16, 2020, and March 13, 2021.
In the most recent study, the researchers found that only 98 of the
658 study participants — 15% — had detectable antibodies to SARS-CoV-2 at 21
days after the first vaccine dose. This was comparable to the 17% reported in
the March study.
At 29 days following the second dose, the number of participants with
detectable antibodies rose to 357 out of 658 — 54%. After both vaccine doses
were administered, 301 out of 658 participants — 46% — had no detectable
antibody at all while 259 — 39% — only produced antibodies after the second
shot.
The researchers also found that among the participants, the most
likely to develop an antibody response were younger, did not take
immunosuppressive regimens including anti-metabolite drugs and received the
Moderna vaccine. These were similar to the associations seen in the single-dose
study.
—Source: Johns Hopkins Medicine
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