  Objectives Influenza outbreaks have been widely studied. However, the
patterns between influenza and religious festivals remained unexplored. This
study examined the patterns of influenza and Hanukkah in Israel, and that of
influenza and Hajj in Bahrain, Egypt, Iraq, Jordan, Oman and Qatar. Method
Influenza surveillance data of these seven countries from 2009 to 2017 were
downloaded from the FluNet of the World Health Organization. Secondary data
were collected for the countries' population, and the dates of Hajj and
Hanukkah. We aggregated the weekly influenza A and B laboratory confirmations
for each country over the study period. Weekly influenza A patterns and
religious festival dates were further explored across the study period. Results
We found that influenza A peaks closely followed Hanukkah in Israel in six out
of seven years from 2010 to 2017. Aggregated influenza A peaks of the other six
Middle East countries also occurred right after Hajj every year during the
study period. Conclusions We predict that unless there is an emergence of new
influenza strain, such influenza patterns are likely to persist in future
years. Our results suggested that the optimal timing of mass influenza
vaccination should take into considerations of the dates of these religious
festivals.
