Improving vaccine safety monitoring systems using mobile health solutions
Recent advances in mobile technology and the growing coverage of mobile phones across the globe present new opportunities for public health surveillance. One such example is the integration of mobile phone use into post-vaccination safety monitoring programs. In 2011, an Australian general practice piloted an active adverse event following immunisation (AEFI) monitoring system which used short message service (SMS) texts to follow-up patients who received a vaccination at that practice.
METHODS:
Between November 2011 and March 2013, all paediatric and adult patients who had received a vaccination at the practice (n=3,291) and provided a mobile phone number (n=3,226; 98.0%) were sent a SMS which asked whether or not they had experienced an AEFI. Patients who replied “yes” as well as those who did not reply to SMS were interviewed by telephone by practice staff.
RESULTS:
Over the two year study period, 72.6% (95% CI: 70.0-75.1%) of vaccinated patients responded by SMS, of which 264 (11.3% [95% CI: 9.9-12.7%]) reported a possible AEFI. The proportion of patients reporting an AEFI by SMS (11.3% [95%CI: 9.9-12.7%]) was statistically similar to the proportion reporting by telephone (11.8% [95%CI: 9.2-14.4%]; p=.99). The rate of AEFI reported decreased as time between vaccination and follow-up increased, although the response rate did not (p=.10). The majority (80.0%) of SMS replies were received within two hours of transmission of the query SMS. SMS response rates were high for both paediatric and adult patients (86.3% and 80.7%, respectively). Response rate remained >70% regardless of the time of day the query SMS was sent.
CONCLUSIONS:
Results from this pilot system indicate SMS is a useful method of data capture for monitoring AEFI and could improve existing AEFI surveillance. Active AEFI surveillance using SMS can be used to complement existing passive reporting systems, enabling more rapid identification of emerging safety signals.