[Technical guidelines for seasonal influenza vaccination in China, 2019-2020].

Abstract

Influenza virus infection is a respiratory infectious disease that can seriously affect human health. Influenza viruses can have antigenic variation and changes frequently, which results in rapid and widespread transmission resulting in annual epidemics and outbreaks in population gathering places such as schools, kindergartens and nursing homes. WHO estimated that seasonal influenza epidemics could cause 3 to 5 million severe cases annually, and 290 000 to 650 000 deaths globally. Pregnant women, young children, the elderly, and persons with chronic illnesses are at high risk for severe illness and death associated with influenza virus infection. Seasonal influenza vaccination is the most effective way to prevent influenza virus infection and complications from infection. Currently, China has licensed trivalent inactivated influenza vaccine (IIV3) which includes split-virus influenza vaccine and subunit vaccine, and quadrivalent inactivated influenza vaccine (IIV4) which is split. Except a few major cities, influenza vaccine is a category Ⅱ vaccine, which means influenza vaccination is voluntary, and recipients should pay for it. In 2018, China CDC issued the Technical Guidelines for Seasonal Influenza Vaccination in China (2018-2019) (Guide 2018). In the past year, new research evidences have been published both in China and abroad, and new seasonal influenza vaccine has been licensed in China. To strengthen the technical guidance for prevention and control of influenza and operational research on influenza vaccination in China, the Influenza Vaccination Technical Working Group (TWG) of National Immunization Advisory Committee (NIAC) updated the Guide 2018 and compiled the Technical Guidelines for Seasonal Influenza Vaccination in China (2019-2020) . Major updates include the following: First, new research evidences especially studies of China, including disease burden, effectiveness, vaccine-avoidable disease burden, vaccine safety monitoring, and cost-effectiveness and cost-benefit. Second, policies and measures for influenza prevention and control issued by National Health Commission (PRC) in the past year. Thirdly, new type seasonal influenza vaccine licensed and issued in 2019-2020 in China. Fourth, northern hemisphere influenza vaccination composition for the 2019-2020 season was updated for both IIV3 and IIV4. The recommendations include: Points of vaccination clinics (PoVs) should provide influenza vaccination to all persons aged 6 months and above who are willing to be vaccinated and do not have contraindications. No preferential recommendation is made for one influenza vaccine product over another for persons whom can accept more than one licensed, recommended and appropriate products. To decrease the risk of severe infections and complications due to influenza virus infection among high risk groups, the recommendations prioritize seasonal influenza vaccination for children aged 6 to 59 months, adults ≥60 years of age, persons with specific chronic diseases, healthcare workers, the family members and caregivers of infants <6 months of age, and pregnant women or women who plan to become pregnant during the influenza season. Children aged 6 months through 8 years require 2 doses of influenza vaccine administered a minimum of 4 weeks apart during their first season of vaccination for optimal protection. If they were vaccinated in 2018-2019 influenza season or prior, 1 dose is recommended. People ≥9 years old require 1 dose of influenza vaccine. It is recommended that people receive their influenza vaccination by the end of October. Influenza vaccination should be offered as soon as available. For the people unable to be vaccinated before the end of October, influenza vaccination will continue to be offered for the whole season. Influenza vaccine is also recommended for use in pregnant women during any trimester. These guidelines are intended for use by staff members of the CDCs at all levels who work on influenza control and prevention, PoVs staff members, healthcare workers from the departments of pediatrics, internal medicine, and infectious diseases, and staff members of maternity and child care institutions at all levels. These guidelines will be updated periodically as new evidence becomes available.