Introduction
Measles and influenza viruses both are infectious diseases which are transmitted among individuals through respiratory route. Measles virus is a single-stranded RNA virus belonging to the Paramyxoviridaefamily [1] which is a highly contagious virus with reproduction number (R0) of 15-18 . Therefore, it is classified as one of the most contagious viruses infecting humankind [2]. Because of the measles vaccination starting at 1968 and effective vaccination mass campaign started in 2003 and the ongoing procedure in Iran, the mortality rate has been reduced considerably to date[3-5], nevertheless measles is still a public health concern.
Influenza viruses belong to the Orthomyxoviridae family. These viruses cause annual epidemics worldwide. Before COVID-19 pandemic, in the United States 5% to 20% of the population were infected with these viruses every year.
The R values of different influenza viruses causing moderate number of illness are different from those causing a high number of illnesses. The median R value for seasonal influenza has been reported 1.28 (IQR:1.19–1.37) [6-8].
Since the beginning of the COVID-19 pandemic, on the one hand, the circulation of the other infectious agents transmitted through the respiratory tract have been reduced by observing quarantine, social distancing and wearing masks. On the other hand, COVID-19 has diverted a huge part of healthcare systems resources and efforts toward pandemic response, disrupted routine immunization services and altered health-seeking behaviors of people worldwide [9, 10].
In October 2019, Iran has achieved the status of measles elimination using effective vaccination strategies and surveillance system based on WHO recommendations[4] . However, during recent months, limited number of measles cases were identified by Iran Measles and Rubella national center. Herein, we report a case of measles and influenza co-infection in a nine month-old infant from Bushehr province of Iran.