Intestinal Immunity Boosted with Extra Polio Vaccination
(HealthDay News) — A single inactivated poliovirus vaccine (IPV) dose improves intestinal immunity for children previously vaccinated with oral poliovirus vaccine (OPV), according to a study published online July 11 in The Lancet.
Jacob John, MD, from the Christian Medical College in Vellore, India, and colleagues conducted an open-label, randomized controlled trial involving healthy children aged 1–4 years who had not received IPV before and had had their last dose of OPV at least six months prior to enrollment. Four hundred fifty children were randomized in a 1:1 ratio to receive 0.5ml IPV intramuscularly or no vaccine. The proportion of children shedding poliovirus seven days after a challenge dose of serotype 1 and 3 bivalent OPV was measured as the primary outcome.
The researchers found that 12 and 8% of children in the IPV group shed serotype 1 poliovirus and serotype 3 poliovirus, respectively, compared with 19 and 26% in the no vaccine group (risk ratios, 0.62 [P=0.0375] and 0.30 [P<0.0001], respectively). There were no study intervention-related adverse events.
"The substantial boost in intestinal immunity conferred by a supplementary dose of IPV given to children <5 years who had previously received OPV shows a potential role for this vaccine in immunization activities to accelerate eradication and prevent outbreaks of poliomyelitis," the authors write.