Past research has suggested that coadministration of vaccines often improves uptake in older adults. In many cases, these patients don’t want to have to make an additional healthcare visit.
A study published in Vaccine evaluated the immunogenicity and safety of the adjuvanted recombinant zoster vaccine (RZV) and the reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine (Tdap) when coadministered in adults aged 50 years and older.
The information is especially timely for pharmacists, given the push for Tdap in older adults, such as grandparents, who have close contact with infants.
For the open-label, multicenter study, industry researchers randomized participants 1:1 to one of the following groups:
• Receiving RZV dose 1 and Tdap at Day 0,
• Receiving RZV dose 2 at Month 2, or
• As a control group, receiving Tdap at Day 0, RZV dose 1 at Month 2, and RZV dose 2 at Month 4.
Researchers were trying to evaluate the vaccine response rate to RZV in the coadministration group while also demonstrating noninferiority of the humoral responses to RZV and Tdap in the coadministration compared with the control group. They also assessed the reactogenicity and safety of RZV and Tdap.
Results suggest that the vaccine response rate to RZV was 97.8% in the coadministration group. At the same time, the noninferiority criterion was met for the humoral response to RZV as well as for four Tdap antigens. This criterion was not met for the Tdap antigen pertactin, however.
The study determined that solicited, unsolicited, and serious adverse events were similar among the groups, as were potential immune-mediated diseases.
“Co-administration of RZV and Tdap did not interfere with the humoral immune response to RZV or 4 of the five Tdap antigens,” the authors conclude. “No safety concerns were identified.”
A study last year in Vaccine evaluated the immunogenicity and safety of RZV when the first dose was coadministered with the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in adults aged 50 years or older, and no immunologic interference was observed in that situation either.
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