Current status of BCG and OPV vaccination in children with primary immunodeficiency in Chongqing, China

This study actively monitors patients with primary immunodeficiency under the age of 18 to understand the risk of adverse reactions after vaccination and provide references for developing vaccination evaluation measures for children with special health conditions. A questionnaire survey was conducted on patients diagnosed with primary immunodeficiency, collecting diagnosis and treatment information as well as the vaccination records of live vaccines. Two stool samples were collected for virus detection and the vaccine-derived poliovirus was analyzed. A total of 26 primary immunodeficiency patients were enrolled among 3312 monitored cases, including 5 cases of severe combined immunodeficiency, 7 cases of primary antibody deficiency, and 14 cases of other types of immunodeficiency. Among the 21 cases with clear vaccination records, the vaccination rate of BCG and oral poliovirus vaccine were 95.24% and 71.43%, respectively. Among them, the vaccination rates of both vaccines for patients with severe combined immunodeficiency were 100% and 60.00%, respectively; and for patients with primary antibody deficiency were 100%. It was found that 1 patient with severe combined immunodeficiency had disseminated BCG infection after vaccination, and type Ⅲ immunodeficiency-associated vaccine-derived poliovirus was detected in his stool samples. The proportion of primary immunodeficiency patients receiving live vaccines is high, and there is a risk of adverse reactions after vaccination. It is recommended to improve the awareness and ability of recognizing vaccination for children with immunodeficiency, promote the active monitoring of children with immunodeficiency in hospitals, and adjust the immunization strategy for polio vaccine in a timely manner.