Does vaccination have to introduce viruses into the body?

Does vaccination have to introduce viruses into the body?

I've heard some people say that getting vaccinated actually puts viruses and bacteria into the body, so you're more likely to get sick after getting vaccinated. Is this true? (Phuong Tra, 58 years old, Hanoi)

Answer:

Vaccines are biological products introduced into the body orally or by injection, helping the immune system recognize and fight future pathogens. Depending on the type, vaccines may contain attenuated pathogens, inactivated pathogens, or only a small part of the virus or bacteria. These ingredients do not cause disease but still activate immunity. Vaccines also have adjuvants and stabilizers to ensure safety and effectiveness, and can protect the injector for many years or for life.

Before implementing measles vaccination (1963), the US recorded 3-4 million measles cases each year, with tens of thousands of hospitalizations and 400-500 deaths. After widespread vaccination, the number of measles cases decreased by about 99%. Rabies vaccine is also the only treatment for rabies.

According to the World Health Organization (WHO), vaccination has saved about 154 million people in 50 years, reducing infant mortality by 40% globally and by more than 50% in Africa, thanks to the prevention of 14 important infectious diseases such as measles, whooping cough, polio, tetanus, hepatitis B... These data show that the reality is completely contrary to the notion that "vaccinations make people more susceptible to disease".

After vaccination, some people may experience pain, swelling at the injection site, mild fever, and short-term fatigue. This is a normal immune response, not a "resurrected" virus or bacteria that causes illness, and most will go away on its own within 1-2 days. The injector may also accidentally cough, have a runny nose or get another illness at the right time after injection, easily causing misunderstandings due to the vaccine.

Vaccines do not make the body weaker, but help the immune system prepare in advance to protect when encountering real pathogens. Therefore, everyone should review the vaccination schedule and get vaccinated at the right time, especially in groups with weak immunity such as children, the elderly, people with underlying diseases and pregnant women.