TORONTO — The order in which consecutive injections of pentavalent and pneumococcal conjugate vaccines are given during the same office visit can significantly impact the amount of pain they cause, Dr. Moshe Ipp said at the annual meeting of the Pediatric Academic Societies.
In a double-blind trial conducted by Dr. Ipp and associates, which was supported by an unrestricted grant from Sanofi Pasteur, 60 infants (aged 2 to 6 months) were randomized to receive either the pentavalent vaccine (DTaP-Hib) followed by the pneumococcal conjugate vaccine (PCV), or the other way around.
Pain was measured using the Modified Behavioral Pain Scale (MBPS) running from 0 (no pain) to 10.
“When you consider these two vaccines, one is more painful [PCV], and one is less painful [DTaP-Hib],” reported Dr. Ipp, a pediatrician at the Hospital for Sick Children, Toronto.
“It's not the needle itself, but it is the vaccine material. We think it's related to pH,” Dr. Ipp said in an interview.
Video recordings of infants receiving the injections demonstrated that, regardless of the order of injections, PCV was more painful that DTaP-Hib, with a score of 8.1 when given first and 9 when given second.
In contrast, the pain score of DTaP-Hib was 6.5 when administered first, and 8.5 when administered second.
The fact that both vaccines were measured as more painful when given second suggests “there must be some priming from the first needle that the child registers,” said Dr. Ipp.
He recommended that since DTaP-Hib is less painful it should be routinely administered before PCV.
“The pain issue and compliance go together, and I think pain has been ignored in the vaccine scenario.
“Reduce the pain and compliance with vaccination will improve,” Dr. Ipp concluded.