Will the side effects increase if multiple vaccines are administered at the same time?

Rumor:

Vaccination of multiple vaccines at the same time will affect the vaccination effect and lead to increased side effects.

Refusing rumors:

Vaccination is currently the most economical and effective measure to prevent and control infectious diseases. Through vaccination, smallpox has been eliminated worldwide, polio has been basically eliminated, and measles has been eliminated in some areas. Many infectious diseases that seriously harm humans, such as hepatitis B, whooping cough, diphtheria, epidemic cerebrospinal meningitis and Japanese encephalitis, have been effectively controlled. As the variety of vaccines on the market in my country continues to increase, vaccination units and recipients are increasingly faced with simultaneous vaccination of multiple vaccines. But when it comes to vaccination, many people still have questions: Will vaccination with multiple vaccines at the same time affect the effectiveness? Will it increase side effects?

Simultaneous vaccine vaccination means that the same vaccinated subject is vaccinated with two or more vaccines in different parts of the body at the same time within one natural day. The World Health Organization's position paper on vaccines, the vaccination schedule recommended by the U.S. Advisory Committee on Immunization Practice and other countries all support simultaneous vaccination of ≥2 vaccines. The "National Immunization Program Vaccine Immunization Procedures and Instructions for Children (2016 Edition)" points out that the current National Immunization Program vaccines can be vaccinated at the same time according to the immunization program or the catch-up principle.

The World Health Organization's "Questions and Answers on Immunization and Vaccine Safety" states: "Scientific evidence shows that vaccination with several vaccines at the same time will not have adverse effects on children's immune systems." Related domestic and foreign studies have also proven , simultaneous vaccination of multiple vaccines is as safe and effective as vaccination alone, and will not reduce the immune response or increase the incidence of adverse reactions. Vaccines are safer than therapeutic drugs when applied to healthy people, and the incidence of serious adverse reactions caused by vaccines is extremely low.

The "National Immunization Program Vaccine Immunization Procedures and Instructions for Children (2016 Edition)" stipulates the principle of simultaneous vaccination: two or more injectable vaccines should be vaccinated at different sites. It is strictly prohibited to mix two or more vaccines into the same syringe for vaccination; if two or more injectable live attenuated vaccines are not administered at the same time, they should be administered at an interval of ≥ 28 days. If inactivated vaccines and oral live attenuated vaccines are not administered at the same time as other types of vaccines (including attenuated and inactivated vaccines), there is no restriction on the vaccination interval. Immunization program vaccines and non-immunization program vaccines can be vaccinated at the same time as long as they do not violate the national immunization program, vaccine instructions, etc. If you choose not to vaccinate at the same time, priority should be given to ensuring the vaccination of the immunization program vaccines.

When multiple vaccines are injected at the same time, they can be vaccinated in the left and right upper arms and left and right thighs respectively. For infants and young children, if more than two vaccines are to be injected into one limb at the same time, the thigh is the preferred site because the muscles here are larger. The distance between the injection sites of the two vaccines should be ≥2.5 cm as much as possible to distinguish the local adverse reactions of different vaccines. In older children and adults, the deltoid muscle may be used for more than 1 intramuscular injection.

After the COVID-19 epidemic broke out in early 2020, provinces, autonomous regions and municipalities across the country successively launched first-level responses to major public health emergencies, and about 80% of vaccination units postponed vaccination services. As the overall situation of domestic COVID-19 prevention and control is improving, routine vaccination work has been gradually resumed in various places, and catch-up vaccinations are being implemented for those who postponed vaccination. Under the current situation, it is even more important to vaccinate multiple vaccines at the same time. Simultaneous vaccination can reduce the number of vaccination shots and reduce children's pain; reduce outpatient crowd gathering and exposure risks, improve outpatient catch-up efficiency and achieve catch-up goals; and ensure the vaccination rate and timely rate of vaccination in the immunization plan.

For those who need to receive multiple vaccines or who have postponed vaccination due to the epidemic, they should try to arrange for multiple vaccines to be vaccinated at the same time and try to use combined vaccines without worrying about adverse vaccine reactions. In addition to vaccinating vaccines included in the national immunization plan, parents should choose other vaccines for vaccination under the guidance of a doctor based on their child's condition.

Rumor-refuting expert: Wu Huizhen, deputy director of the Department of Pharmacy, Hebei Provincial People's Hospital, chief pharmacist

Review expert: Guo Yifang, deputy director, chief physician of Hebei Provincial People's Hospital

References:

1. "National Immunization Program Vaccine Immunization Procedures and Instructions for Children (2016 Edition)"

2. "Guiding Opinions on Simultaneous Vaccination of Multiple Vaccines in Guangdong Province ( 2019 edition)》