Why do babies get the flu after getting the flu vaccine?

As we all know, the flu vaccine is an important way to protect your baby from the flu. In the flu season, many parents are wondering: why has the baby been vaccinated against the flu, or got the flu? Here's a scientific look at the phenomenon, as well as when and when to get the flu vaccine.

First, why can my baby still get the flu after getting the flu vaccine?

The vaccine is a limited match to the virus

Influenza vaccines are not a universal shield. The formulation of vaccines is based on the main circulating strains predicted by the World Health Organization based on global influenza surveillance, and vaccines are prepared accordingly. However, there may be some deviation between the forecast and the actual epidemic strains, and may not be a complete match, resulting in a reduction in the protective effectiveness of the vaccine. Influenza viruses are highly variable, and if the virus mutates during an epidemic, the protective effect of the vaccine may be reduced. Even with the vaccine, your baby can still be infected with a strain that is not covered.

Vaccine protection is limited

Even if the vaccine antigen is a perfect match for the circulating strain, it will not provide 100% protection, and flu vaccines are generally between 50% and 70% protective, and the main goal is to reduce the risk of severe flu or complications, rather than completely avoiding infection. Even when infected with the flu, vaccinated babies usually have milder symptoms and recover more quickly.

The immune response was not fully established

After your baby is vaccinated, it takes about two to four weeks for the body to build immune protection, and if you are exposed to the flu virus during this time, you may still contract the flu.

Attenuation of immunity

After getting the flu vaccine, the immunity you gain diminishes over time. The degree of attenuation is related to factors such as age, physical condition and vaccine antigen. After 1 year, serum antibody levels were significantly reduced, and the influenza vaccine given in the previous season did not provide protection in the current season.

Other viruses cause similar symptoms

Some other respiratory viruses (such as rhinoviruses, adenoviruses, or respiratory syncytial viruses) can also cause flu-like symptoms, but these viruses are not covered by the flu vaccine.

Second, the significance of influenza vaccination

Although influenza vaccination is not 100% protective against infection, it is still an important measure to protect your baby's health, especially the following:

Reduces the risk of serious complications

Influenza can cause serious complications such as pneumonia, otitis media, myocarditis, and shock. Vaccines can significantly reduce these risks.

Protect people with weakened immunity

Vaccination can not only protect the baby, but also reduce the spread of the virus and indirectly protect high-risk groups such as the elderly and pregnant women.

Reduce symptoms and shorten the course of disease

Vaccinated babies usually have milder symptoms and shorter recovery times even when they get the flu。

Vaccinated babies usually have milder symptoms and shorter recovery times even when they get the flu

Best time to vaccinate

The peak time and duration of influenza activity vary across China each year. Generally, seasonal influenza occurs between October and May of the following year, with a peak in January and February. The flu vaccine is usually available for vaccination from September to November, and early vaccination is recommended because it takes approximately 2-4 weeks for the body to produce enough antibodies to be protective after vaccination. Vaccinating your baby before the flu season so that your baby has the ability to resist the virus when it hits.

Age and vaccination requirements

Babies over the age of 6 months can get the flu vaccine. Infants vaccinated for the first time (6 months to 8 years) need two doses of the vaccine at least 4 weeks apart to be fully protected. Babies over the age of 8 or who have previously received the flu vaccine only need one dose per year.

Children under 6 months of age should not be vaccinated against influenza. Mothers are vaccinated against influenza during pregnancy and lactation, and the antibodies produced are passed to the fetus through the placenta and breast milk, providing a certain degree of protection for the baby within 6 months of birth. Vaccination of family members and caregivers can reduce the spread of the virus and protect babies up to 6 months of age.

A dynamic look at the flu season

If you miss the best vaccination time, as long as the flu season is not over (usually until May of the following year), you can still get vaccinated to get some protection.

Fourth, how to improve the protective effect of influenza vaccine?

Follow the doctor's advice to complete the vaccination

Follow the doctor's advice to complete the vaccination

Comprehensive protection measures will be strengthened

In addition to vaccinations, babies should develop good hygiene habits, such as washing hands frequently, avoiding contact with sick people, and maintaining indoor air circulation.

Maintain a healthy lifestyle

Adequate sleep, a balanced diet and moderate exercise can help boost your baby's immunity.

V. Conclusion

The flu vaccine is not a "miracle cure," but it is an important barrier to protect your baby's health and reduce the severity of the flu. Even if the vaccine can't completely avoid infection, it can help your baby reduce symptoms and reduce the risk of complications. Every year from September to November is the best time to get the flu vaccine, in the absence of contraindications, parents should arrange for the baby vaccination as early as possible, combined with other protective measures, to jointly resist the flu threat.