Deaths reported after pentavalent vaccine compared with death reported after diphtheria-tetanus-pertussis vaccine: An exploratory analysis

Abstract

Introduction: Immunization is one of the most effective public health tools available to prevent death and disease. Serious adverse events following immunization (AEFI) are rare. However, coincidental sudden-infant-death-syndrome (SIDS) deaths do occur temporally associated with vaccination. In 2010, the Government of India (GoI) introduced a new standard operating procedure (SOP) to report AEFI. There have been stray newspaper reports of deaths soon after the administration of the pentavalent vaccine (PV) which was introduced by the GoI in December 2011. This study was conducted to examine if there is an epidemiological signal from the data collected passively under the new SOP. Materials and Methods: We used data provided by the GoI on the number children who received three doses of diphtheria-tetanus-pertussis vaccine (DTP), the number receiving PV and the number of deaths in the vaccinated within 72 h. Results: After PV was introduced in the states, 45 million infants received DTP vaccination and 25 million received PV. There were 217 deaths within 72 h after DTP was administered and 237 following PV. There were 4.8 deaths per million vaccinated with DTP (95% confidence interval [CI]: 4.2–5.5) and 9.6 deaths (95% CI: 8.4–10.8) per million vaccinated with PV (odds ratio 1.98 (95% CI 1.65-2.38) There were 4.7 additional deaths (95% CI: 3.5–5.9), per million, vaccinated with PV instead of DTP (P < 0.0001). Discussion: Deaths following DTP vaccination would include the natural rate of deaths within that window period, plus deaths if any, caused by DTP. For purposes of this study, we assumed that all the deaths associated with DTP are coincidental SIDS deaths. Taking that as the base rate of SIDS, we look for any increase in the death rate after PV. This study demonstrated an increase in reports of sudden unexplained deaths within 72 h of administering PV compared to DTP vaccine. Whether improvements in AEFI surveillance system or other factors contributed to this increase cannot be ascertained from this study. Conclusion: These findings do not warrant deviation from current vaccination schedule, but the differential death rates between DTP and PV do call for further rigorous prospective population-based investigations.

Keywords

• Adverse events following immunization
• pentavalent vaccine
• TOKEN study