Vaccine safety monitoring in pregnant women using text messaging
The World Health Organisation lists pregnant women as the highest priority for seasonal trivalent influenza vaccination (TIV). Despite the benefits to mother and infant, more than 75% of pregnant women go unvaccinated each season. Safety concerns are commonly cited as a barrier. In 2012, the Western Australia Department of Health initiated the Follow-up and Active surveillance of Trivalent influenza vaccine in Mums (FASTMum) program to monitor vaccine safety in pregnant women annually. While successful, this program was time-intensive and costly. In 2013, the use of short message service (SMS) was investigated as a method for collecting information.
METHODS:
Between March and July 2013, 3,446 pregnant women were surveyed regarding their TIV experience; 3,047 women provided a mobile telephone number and were sent a SMS query asking if they experienced an adverse event following immunisation; Women who responded “yes” (n=301) or did not reply, and women who provided only a home telephone number (n=126) were contacted by telephone to ascertain details regarding the event.
RESULTS:
Four in five women who agreed to participate in the program responded to the query SMS; 8.7% of the women reported a mild adverse event: 3.5% injection site reaction, 2.7% headache, 2.0% fever, 2.1% fatigue. All other events were rare (<1%). Events reported by SMS did not differ to events reported by telephone, with the exception of injection site reaction. Women who responded by telephone were 10.1 times (95% CI: 2.5-44.0) as likely to report swelling or pain at the injection site compared to women responding by SMS. The use of SMS resulted in a 7-fold increase in sample size and 36% reduction in cost.
CONCLUSIONS:
Results support the safety of TIV in pregnant women and suggest mobile phone technology may be useful in implementing an annual rapid, active monitoring system. Considering the low level of adverse events reported, these findings could be useful in promoting vaccine uptake in pregnant women.