Turning up the heat: Effect of new vaccine for children's (VFC) program recommendations for use of temperature monitors upon incorrect product storage adverse event reporting.

Background: The Centers for Disease Control and Prevention (CDC) coordinates the Vaccines For Children (VFC) program, which provides free vaccines to qualified children in the US. In 2009, the CDC issued Vaccine Storage Requirements, which were later replaced (2012) with an interim guidance and toolkit for vaccine storage and handling. The guidance called for use of Digital Data Loggers (DDL) to monitor vaccine storage temperatures. We describe a change in frequency of Incorrect Product Storage Reports (IPSRs) following issuance of the 2009 CDC guidance.

Methods: Merck & Co., Inc., Kenilworth, NJ, USA, systematically evaluates vaccine safety concerns for all products. The safety database was queried (01-Jan-2004 through 31-December-2016) to identify all IPSRs associated with 10 vaccines. We compared IPSRs received prior to and following the 2009 CDC guidance, comparing reports received from the US with those received from international sources during the same period.

Results: Following the release of the DDL guidance, a progressive increase in IPSRs was identified in the US (1 report received in 2004, 12,993 reports in 2016). In contrast, non-US IPSRs - have not had a similar increase: no reports received in 2004, 216 reports received in 2016. US reports of IPSRs 2004 through 2016 account for 96% of reports worldwide. There were no serious reports found in the database in conjunction with IPSRs, nor were there any additional safety findings in any of the reports with additional events reported.

Conclusion: VFC DDL guidance was followed by an increase in IPSRs. No similar trend was seen outside the US (where no broad change in DDL guidance occurred). Despite the increase in IPSRs, there have been few associated adverse events (AEs) reported; no new safety concerns were identified. These findings suggest that the increase in IPSRs was associated with the introduction of use of DDLs, and suggests the need for further impact assessment.