Do you want to get the flu vaccine？ Is there still time to call？ How old do children need vaccination？

Original emergency department Zhejiang University Children’s Hospital

Recently, the flu has become the focus of parents’ attention. Wu Xiujing, director of the emergency department of Zhejiang University Children’s Hospital, said: The patient who came to the emergency room for rescue recently because of high fever is not a case.

Parents often ask her anxiously: Why does a child’s fever push 41℃? Once caught in a stream, is it inevitable? A stream, is it really inevitable and impossible to prevent?

Seeing that parents are so helpless and anxious, Director Wu Xiujing’s team brought this issue of popular science to parents’ concerns.

Wu Xiujing, director of emergency department, chief physician

Specialty: Engaged in clinical, scientific research and teaching in pediatrics for more than 20 years, with rich clinical experience in perioperative diagnosis and treatment of common diseases in pediatrics and congenital heart disease in children, especially with high level in diagnosis and treatment of critical diseases in pediatrics, and good at the rescue and monitoring of newborns, various pediatric internal medicine and perioperative critical patients with congenital heart disease in children.

Outpatient service time: Wednesday all day, Friday morning (Binjiang Campus)

Do you want to fight or not? First of all, understand the flu ≠ cold.

Wu Xiujing said that influenza is a highly contagious respiratory disease, which is caused by influenza virus. There are three main types of influenza viruses: A, B and C, of which A and B are the most common influenza viruses. Judging from the recent epidemic situation, most of them are H1N1.

Influenza ≠ cold, influenza is prone to acute onset, usually accompanied by high fever and chills. In addition, there will be respiratory symptoms, such as cough, sore throat and stuffy nose. Some children will also have systemic symptoms, such as muscle pain, headache and extreme fatigue. In addition, the flu is more prone to high fever than a cold, and the situation of reaching 41 C does exist, which not only makes parents feel scared, but also threatens the safety of their children.

The mechanism of influenza vaccine is to stimulate the immune system to produce antibodies against influenza virus, thus effectively reducing the chance of infection or alleviating symptoms when exposed to the virus.

After understanding this knowledge, many parents actually have an answer in their hearts about whether to fight or not.

Do you have to fight every year?

The first thing to understand is that the virus is constantly mutating.

Whether the vaccine should be given every year is a problem that parents are very concerned about.

Wu Xiujing said that to answer this question, parents should first be asked to understand the rapid variation of influenza virus. Because the influenza virus is constantly mutating, the annual influenza vaccine will be updated according to the global influenza monitoring data. According to the components contained in the vaccine, it is divided into trivalent and tetravalent influenza vaccines, and scientists will choose vaccine components according to the predicted mainstream virus strains.

Therefore, the flu vaccine needs to be given every year.

When is the best time for vaccination?

First of all, we need to know when the vaccine works.

Many parents are concerned: Is it too late to get vaccinated now? When is the best time to get vaccinated?

Wu Xiujing said that if parents want to know this information, they must first understand the time when the vaccine works and the time to maintain it.

"Generally speaking, vaccines usually start to work two weeks after vaccination, and the antibody protection level can last for at least six months after vaccination with influenza vaccine."

Therefore, she said, it is best to complete immunization before the local flu season, such as early autumn, to ensure that immunity is established before the flu season. Of course, children can still be vaccinated at any stage of the epidemic season, which can produce protection.

Therefore, it is still not too late to vaccinate at this stage.

Which vaccine is the best choice?

First of all, we must understand the applicable age of different vaccines.

Wu Xiujing said that at present, influenza vaccines can be divided into two types. One is an injection vaccine, usually an inactivated vaccine, which contains the killed virus. There are trivalent inactivated vaccine (IIV3) and tetravalent inactivated vaccine (IIV4) on the market, which can be used for vaccination of people over 6 months old. The other is nasal spray vaccine, which contains live attenuated virus. Currently, trivalent live attenuated vaccine (LAIV3) is listed in China, which is suitable for people aged 3-17.

How many doses of flu vaccine does the child need?

Children aged 6 months to 8 years who are vaccinated with influenza vaccine for the first time should be vaccinated twice (the vaccine of the same dosage form should be selected for two doses), and the interval between two doses should be ≥4 weeks; Children who have received one or more doses of influenza vaccine in 2022- 2023 or before are recommended to receive one dose. For nasal spray vaccine, no matter whether you have been vaccinated with influenza vaccine or not, only one dose is given. Children and adults aged 9 and over only need to be vaccinated with one dose of influenza vaccine.

How old is the child to be vaccinated?

First of all, we should know who are the key and high-risk groups.

Director Wu Xiujing suggested that almost all people aged 6 months and above should be vaccinated against influenza every year.

It is especially recommended that the following key and high-risk groups be vaccinated in time:

1 medical personnel, including clinical rescue personnel, public health personnel, health and quarantine personnel, etc.;

2. Older people aged 60 and over;

3. People suffering from one or more chronic diseases;

4. Vulnerable people and employees in gathering places such as old-age care institutions, long-term care institutions and welfare homes;

5. Pregnant women;

6. Children aged 6-59 months

7. Family members and caregivers of infants under 6 months old;

8. People in key places such as kindergartens, primary and secondary schools and supervision places.

Attachment: Questions and answers about other knowledge

1. What circumstances should we postpone or prohibit vaccination?

The safety of influenza vaccine has been strictly examined, and the side effects are usually mild. Common adverse reactions include: pain and redness at the injection site; Transient low fever and fatigue. Individual children will have rare serious reactions: such as allergic reactions. Egg allergy is not a taboo for influenza vaccination, but children who have the following conditions should pay special attention:

Anyone who is allergic to any ingredients contained in the vaccine or who has had a history of severe allergy to any kind of influenza vaccination is prohibited from vaccination.

Patients with acute diseases, acute attack of chronic diseases and fever are advised to be vaccinated after recovery or stable disease control.

Nasal spray vaccine (live attenuated vaccine) is contraindicated for the following groups:

① Persons with low immune function due to drug use, HIV infection and other reasons;

② Children and adolescents who have been treated with drugs containing aspirin or salicylic acid for a long time;

③ Children with asthma aged 2-4 years;

4 pregnant women;

⑤ Those with a history of Guillain-Barre syndrome;

⑥ Those who used antiviral drugs such as oseltamivir and zanamivir 48 hours before inoculation, or those who used palamivir 5 days before inoculation, or those who used balosevir 17 days before inoculation.

2. Will influenza vaccination cause influenza?

Vaccination does not contain live virus and will not cause influenza. If you feel pain or low fever, this is the normal response of the human immune system to the vaccine, which usually lasts only one or two days.

3. Does the flu vaccine have serious side effects?

The flu vaccine is safe. Serious side effects are extremely rare. One person in every million people may suffer from Guillain-Barre syndrome (GBS), resulting in muscle weakness and paralysis.

4. After vaccination, but still infected with the flu, does it mean that the vaccine doesn’t work?

Many different influenza viruses have been spreading every year. Although people are vaccinated, they may still be infected with influenza, because the infected strains are not included in the vaccine. However, even if you are infected with influenza after vaccination, your symptoms will be mild, reducing the risk of serious complications. Moreover, influenza vaccination can also protect people with weak immune systems, such as children and the elderly at home.

Tips: Influenza vaccine is one of the most effective means to prevent influenza, which provides important protection for personal health and public health. It is everyone’s responsible behavior for himself, his family and the community to actively vaccinate against influenza every year.

Contributed by Zhang Nan, Emergency Department

Original title: "Influenza vaccine, do you want to fight? Is there still time to call? How old do children need vaccination? The answers are all here! 》

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