Laboratory response to an infant with suspected measles vaccine associated fever and rash in Sri Lanka

Background:Measles is a highly contagious illness. Sri Lanka (SL) has eliminated the measles in 2019. The country is at risk of importation of measles and there could be vaccine-associated measles like illnesses. Therefore, it is important to investigate patients with fever, rash to differentiate the wild-type from vaccine-type excluding other suspected pathogens to direct infection prevention and control strategies. The objective is to describe the laboratory investigation procedure in an immunocompetent child, developed fever, rash following measles containing vaccine in post-measles eliminated period, SL. Methods:This laboratory based investigation was carried out in National Measles Laboratory, SL. Blood and throat swab were received from a patient with fever, rash, cough and coryza developed at tenth day of receiving the measles containing live-attenuated vaccine. Samples were tested for measles, rubella, and other relevant pathogens according to the laboratory testing algorithm for an immunocompetent child with fever, rash and flu like symptoms. Results:Measles vaccine type A, Edmonston-strain virus was detected after sequencing in throat swab and measles IgM and IgG were positive at sixth-week of illness-onset. In addition, influenza A RNA was detected in throat swab at day-three with detectable parvoB19 IgM in blood sample received at sixth-week of post-onset symptoms. Conclusions:Measles like illness of this immunocompetent child who received measles containing vaccine could be due to measles vaccine-type A or influenza infection. In a measles eliminated, resource-limited setting in SL, there should be a well-defined, testing algorithm to exclude prevalent possible pathogens according to epidemiological and clinical information.