“Routine vaccines may have nonspecific effects on mortality,” Najaaraq Lund, MD, PhD, of the department of pediatrics at Kolding Hospital, Denmark, and colleagues wrote in Clinical Infectious Disease. “Administration of oral polio vaccine-at-birth, particularly in the first days of life and in the absence of oral polio vaccine campaigns, may have a marked beneficial impact on infant survival.”
The researchers studied a cohort of 6,961 newborn children from Guinea-Bissau during a 12-month period. To determine the associations between mortality and oral polio vaccine (OPV) at birth, researchers divided the cohort into two groups: a variable group who only received bacille Calmette-Guérin vaccine at birth (n = 3,467), and controls who received bacille Calmette-Guérin vaccine and OPV at birth (n = 3,494).
Study results showed that within 12 months, 73 children who received both bacille Calmette-Guérin vaccine and OPV at birth died, whereas 87 children who received only bacille Calmette-Guérin vaccine at birth died. All study-associated mortality was a result of infectious diseases. The HR when comparing bacille Calmette–Guérin vaccine plus OPV at birth to only bacille Calmette–Guérin vaccine was significantly high (HR = 0.83; 95% CI, 0.61-1.13), with the risk greater in girls (HR= 0.97; 95% CI, 0.61-1.54) than in boys (HR= 0.72; 95% CI, 0.47-1.1).
The researchers said these results suggested that OPV at birth is not only safe for the prevention of poliovirus, but also has nonspecific benefits against the contraction of other infectious diseases, raising concern about the global strategies to eradicate polio.
“The Global Health Community intends to replace OPV with inactivated polio vaccine in the endgame for polio because the attenuated virus in OPV in rare cases can cause vaccine-associated polio paralysis,” Lund and colleagues wrote. “If OPV at birth has beneficial nonspecific effects, this strategy may have negative effects on overall survival.”
In a related editorial, Lawrence D. Frenkel, MD, of the department of pediatrics and microbiology at the University of Illinois College of Medicine, suggested that these findings will bring relief to vaccine advocates.
“[A previous study] was disconcerting to vaccine advocates around the world both for the possible detrimental effect on the control of polio disease in the few remaining endemic countries and because it could give additional fodder for anti-vaccine groups,” Frenkel wrote. “[This study] reports the opposite, a protective effect of oral polio vaccine given within 2 or 3 days of birth, an overall (uncensored) reduction in mortality of 16% by specifically decreasing male infant mortality.”