OBJECTIVES

To assess the potential signals of death associated with different vaccines in Vaccine Adverse Event Reporting System database (VAERS) by data mining algorithms.

METHODS

The analysis was executed on fifty-four vaccines that has been approved during the time period of 1990-2017. The data was retrieved from publicly available VAERS database. The suspected vaccines were discerned by obtaining VAERS ID of death reports from symptom file of the database. Death has been associated with a total of fifty-four vaccines. A minimum of thirty death reports were the pre-requisite to consider a Vaccine Event Combination (VEC) as clinically relevant. This resulted in twenty vaccines by excluding thirty-four vaccines having death reports below thirty. The two most commonly used data mining algorithms, namely, Reporting Odds Ratio (ROR) and Proportional Reporting Ratio (PRR) were applied retrospectively in VAERS. A value of ROR-1.96SE>1 and PRR≥2, χ2>4 were considered as positive signal.

RESULTS

The VAERS database is comprised of 5,41,192 VECs which were reported from 1990-2017. Among which, 1321 reports were death associated with different vaccine types. On analysis, death associated with thirteen vaccines showed positive signal as the signal value were well above the pre-set threshold. Rotarix (RV1) (ROR-1.96SE: 6.12, PRR: 8.6) and Diphtheria, Tetanus, acellular Pertussis, Polio and Haemophilus influenzae type b (DTaP - IPV – Hib) (ROR-1.96SE: 5.67, PRR: 7) exhibited maximum signal strength.

CONCLUSIONS

The disproportionality analysis aided in identification of the possible adverse event (death) associated with vaccination. The result warrants an integration of clinical studies for the validation and quantification of possible risks of vaccines associated death. Although a causal relationship cannot be established, the number of cases reported suggests that there might be an association between the vaccines and death. Hence, health care professionals must be warier about the prospect of encountering death with the identified vaccines.