A netizen in Sichuan consulted me, his baby refused the free attenuated hepatitis A vaccine at the age of 18 months, and received the self-funded inactivated hepatitis A vaccine, the manufacturer is Merck & Co., Ltd. of the United States, and now he is two years old to receive the second dose of hepatitis A inactivated vaccine.
Regarding the use of vaccines from different manufacturers to complete the full course of vaccination, the guiding principle in the actual work process is: try to use the vaccine of the same manufacturer to complete the full course of vaccination, if there are special circumstances (such as changing the vaccination clinic, or the original manufacturer stops supply), you can choose the same process vaccine of different manufacturers to complete the vaccination, this principle is mainly applied to non-immunization program vaccines (self-paid vaccines), because immunization program vaccines (free vaccines) are all unified procurement and distribution, and parents do not have to choose.
Of course, the second dose of inactivated hepatitis A vaccine can be made domestically, and the premise is that the vaccination staff needs to inform the netizen before vaccination. Then this netizen asked me a second question: Is there any data to confirm that Merck & Co., Ltd. and Sinovac have one shot of hepatitis A inactivated each, and whether there is any difference in safety, efficacy and general response compared with two shots of the same manufacturer?
Being able to ask this question shows that this netizen has done some homework. In Sichuan, if you are vaccinated with the attenuated hepatitis A vaccine at the age of 18 months, it is free of charge, and only one shot is required for the whole process, while if you choose the self-paid inactivated hepatitis A vaccine, you need two shots for the whole process, with an interval of more than six months. This netizen also chose to pay for it at his own expense because of the better safety of the hepatitis A inactivated vaccine.
If you have to answer the second question of netizens, you need to do a comparison of the clinical trials of hepatitis A inactivation of Merck and Sinovac after vaccination, this kind of clinical trial is rarely done by scientific researchers, and I have not found relevant literature at present. However, there are similar cases, such as a study done in Shanghai, which confirmed that simultaneous or alternating administration of the French Pasteur Salk inactivated polio vaccine and the domestic SABIN inactivated polio vaccine have good immunogenicity, as shown in the figure below.
If parents are more concerned about changing the manufacturer of the follow-up dose of the self-paid vaccine, they can inform the vaccination doctor clearly when receiving the first dose, so that it is convenient to take measures, such as reserving the corresponding vaccine to meet the parents' wishes. Therefore, more communication before vaccination can indeed reduce a lot of troubles and misunderstandings in the follow-up.