Why does the temperature rise after a flu shot?

With the beginning of large-scale vaccination against coronavirus infection, many new questions began to arise about how to behave after vaccination and what to pay attention to. Despite reviews indicating that in most cases vaccination takes place without consequences, some vaccinated people experienced side effects after the introduction of the newly developed product.

Most often, patients note fever, concomitant weakness, chills, headaches and muscle pain. Why does the temperature rise after vaccination against coronavirus, is it normal or pathological, when should it be brought down and other features of vaccination are discussed below.

Vaccination

To understand why your temperature rises after a flu shot, you need to know how the shot itself works.

The human immune system is necessary to detect pathogenic organisms and neutralize them. When a virus or antigen enters the body, the immune system reacts to it by releasing antibodies into the bloodstream. It is at this moment that a person experiences an increase in temperature. After the immune system has overcome an infection, it develops a certain resistance to it.

It is resistance to the virus that is developed after the vaccine is introduced into the body. Why is stability not maintained for life, and a person is forced to come to the treatment room every year? The main reason for this is the fact that the flu strain changes every year. Moreover, it is impossible to develop a vaccine that will completely destroy the future strain of the virus. But thanks to the efforts of epidemiologists, the likelihood of the vaccine being effective is very high.

Is it possible to give several vaccinations at the same time? Quite. Along with the flu shot, you can get vaccines against rubella, measles, mumps, and polio. But all of them must be inserted with syringes and into different parts of the human body.

Features of the flu vaccine

Along with the first cold weather, colds come to us. The most insidious of them is the flu. An influenza epidemic occurs annually in the autumn-winter period. The spread of the virus is facilitated by large crowds of people indoors and reduced immunity, the level of which falls due to a deficiency of vitamins and sunlight. The most reliable way to protect yourself from the virus is vaccination. And although it is not mandatory, most doctors recommend it.

The main feature of the influenza virus is its ability to mutate. Every year it changes, therefore, having had the flu several times, we acquire only partial immunity and remain defenseless against the new strain.

Once every 30-40 years, the influenza virus mutates abruptly, and during this period there is a pandemic, i.e., an epidemic that covers many countries and even continents. In order to create highly effective vaccinations, WHO conducts annual monitoring of circulating strains of the influenza virus and, based on laboratory analysis, formulates recommendations on the composition of the vaccine for the current year.

Several decades ago, the first vaccine was developed and tested. It contained live but weakened viral particles. Vaccination with this drug was poorly tolerated by children, the elderly and persons with reduced immunity.

Today, live vaccines are practically not used. They have been replaced by inactivated vaccines, which contain split, lifeless viral particles. Such vaccines reduce the risk of side effects to a minimum and create a complete immune barrier against infection.

All vaccines used today can be divided into 2 large groups:

Split vaccines, for example, Vaxigripp (France), Begrivac (Germany), Fluarix (Belgium);
Subunit, such as “Influvac” (Holland), “Agrippal” (Germany), “Grippol” (Russia), etc.

Such vaccines have the fewest side effects.

It takes about 10 days for the human body to develop immunity. It is best to get vaccinated about a month before the expected epidemic. Adults only need one injection; children under 6 years of age need to be vaccinated twice with an interval of 4 weeks.

Influenza vaccination is recommended for everyone, but especially for the following categories of people:

Children (the child’s immunity is not yet fully formed);
Elderly people (especially after 60-65 years, when the immune system is already weakening);
People with diseases of the immune system, diabetes.

The optimal time for administering the vaccine is early autumn (October-November). However, vaccination is not prohibited at a later date. The preventive effectiveness of vaccination is 70-90%. With 50-80% vaccination coverage of groups, the effect of collective immunity was noted.

The following are eligible for free annual flu vaccination:

Pupils;
Students;
Workers of medical and educational institutions, transport, public utilities, etc.;
Elderly people over 60 years of age.

Until recently, the only strict contraindication for flu vaccination was an allergy to chicken protein. But in recent years, infant vaccinations have been done without this substance. Several different vaccines are developed every year, so it is possible to choose a drug that is suitable in composition for almost every person. You can learn about the flu vaccine Sovigripp in this material.

Increase in temperature after vaccination

If your temperature rises after getting a flu shot, there is nothing strange or pathological about it. Despite the fact that the virus in the vaccine is inactive, killed or very weak, the body perceives the drug as a foreign protein that needs to be fought.

This is exactly how the body’s natural defense mechanism against the influenza virus is formed: when the virus enters the body naturally from the source of infection, the immune system can quickly overcome the antigens.

When not to worry

If after vaccination the temperature begins to rise, then the effect of the immune response is manifested, the antigens that have entered the blood are killed. When the real virus enters the body, it will already be ready, and then a flu-like fever will appear. When a vaccine is administered and adults develop a fever, it is better to endure it and not bring it down. While fever in children is more dangerous, as it can cause seizures.

Hyperthermia can be caused by the following factors:

the vaccination was given against the background of a cold;
antigens are administered to a patient who is already a carrier. This situation is very rare, since the incubation period of influenza is on average 3 days, and such coincidences are unlikely;
stress from vaccination (more often in children).

In these cases, there is no need to sound the alarm. If you take an antipyretic drug, everything will go away. The fever can last up to three days.

Does the temperature always rise after vaccination?

The reaction to a vaccine depends on many factors, as well as the severity of symptoms against the background of a particular disease. The adaptation systems of an organism weakened as a result of the administration of vaccination serum may behave differently.

Therefore, one person will not experience any discomfort after vaccination, while another will experience an increase in body temperature.

But it is important to know that various factors can play a role in the reason why the temperature rises after a flu shot. And in order to correctly assess your well-being, you need to consider all these factors.

Stress after vaccination

Sometimes a rise in temperature after a vaccine is a reaction to stress. For example, if a person experiences emotional discomfort when visiting a medical facility, the natural physiological response to stress will be the activation of the sympathetic nervous system and, as a result, an increase in temperature.

For an adult, this situation is rare, but in a child, a fever after a flu shot happens quite often.

Warning signs

A fever after a flu shot in an adult or child is not the only warning sign that you should pay close attention to.

Symptoms that indicate an abnormal response of the body to the influenza vaccine include:

nausea and vomiting;
diarrhea and abdominal pain;
weakness;
dizziness and fainting;
itching and rashes on the skin;
change in skin color to yellowish, blue or green;
A lump appears at the injection site.

If such signs appear, you should immediately consult a doctor. The most likely cause of such somatic manifestations is an infection in a latent form that was already present in the body.

Causes of fever during influenza

An increase in temperature during illness is a completely common situation, thus the body activates its protective function to fight infection.
A similar situation occurs after vaccination and is called a post-vaccination reaction. There are three main reasons why fever appears after vaccination:

Entry into the body through injection of an antigen that provokes the production of immunity and the necessary antibodies, but is essentially not dangerous, since it consists of significantly weakened bacteria (virus) or their protein fragments. In this case, an increase in temperature no higher than 37.5C and the presence of symptoms similar to acute respiratory infections or acute respiratory viral infections are considered normal.
An existing cold (even in incubation form) weakens the body and, accordingly, the reaction to the vaccine in this case will be more acute. Most often, this is the main reason for the appearance of fever in children, but parents do not always notice the first signs of a cold, and their active manifestation immediately after vaccination is attributed to its “negative” effect. In this case, only a doctor can determine the true cause of the increase in temperature and prescribe the necessary treatment.

You should definitely seek medical help if you have the following symptoms:

nausea, stomach pain, diarrhea appear;
the thermometer reading is above 38C and does not subside within three hours;
the appearance of severe weakness;
change in skin color;
severe headaches;
the appearance of a lump or lump at the injection site, as well as a painful reaction.

3. Another reason for the rise in mercury on a thermometer in children is a stressful situation. The child's moral unpreparedness for this medical procedure causes a strong response in him, including provoking the appearance of fever. As a rule, it does not last long and goes away the next day. As a preventative measure in this case, you can give the child a mild antipyretic drug once.

The reaction of a child’s body will always be more active than an adult’s, especially after the very first vaccination. Therefore, it is recommended to vaccinate children with inactivated vaccines that do not contain live pathogens.

How to avoid complications?

To avoid situations where, after a flu shot, the temperature rises above 37 degrees, you need to know exactly the list of contraindications to vaccination:

acute period of any disease, including exacerbations;
serious pathologies of internal organs (lungs, liver, kidneys, heart) in a chronic form;
immunodeficiency;
autoimmune diseases;
atherosclerosis and hypertension;
allergy to chicken protein;
pregnancy in the last trimester.

Why can’t the vaccine be administered during an exacerbation of the disease? The fact is that any active pathology in the body is always accompanied by an increase in immune activity. Therefore, the reaction to the injected serum may be brighter and more pronounced.

The attending physician should speak to the patient about precautions, contraindications and side effects before vaccination. If you have doubts about the advisability of vaccination due to certain diseases, you should definitely discuss this issue with your doctor.

Flu prevention

Flu is easier to prevent than to treat. To do this, it is recommended to observe personal hygiene measures:

Always wash your hands with soap after returning from the street;
Avoid contact with sick people;
Regularly carry out wet cleaning in the house;
If you need to visit a crowded place during a flu epidemic, you can wear a medical mask.

The mask needs to be changed every 3-4 hours. Otherwise, the viruses accumulated in it can penetrate the respiratory tract and cause illness.

However, because influenza is so easy to catch, practicing good personal hygiene cannot guarantee protection against the virus. Therefore, it is recommended to get vaccinated against this disease before the start of the autumn-winter season. Vaccination is especially necessary for people who are at increased risk of contracting the flu. This category includes:

Children and adolescents under 16 years of age;
Elderly people over 50 years of age;
Medical workers, teachers and people whose profession involves being in crowded places;
People with weakened immune systems and chronic respiratory diseases.

Children receive the flu vaccine after they reach 6 months of age. It is better to use split vaccines, as they cause fewer adverse reactions due to the lack of preservatives. This drug contains only inactivated (dead) particles of the pathogen, so it is impossible to get the flu from the vaccine.

The French vaccines Vaxigrip and Fluarin are used to vaccinate children. The first vaccination is given 1-2 months before the start of the autumn-winter season, the drug is re-administered a month after the first dose. Immunity after vaccination lasts only 8-10 months, so every year it is necessary to re-vaccinate.

Vaccines are also used: “Sovigripp”, “Grippol”, “Ultrix”, “Influvac”, etc.

For more information about vaccinating children against influenza, watch the video:

Adults are vaccinated with the same drugs as children, but in higher dosages. Vaccination with split vaccines can be done in mid and late stages of pregnancy. In the first trimester, vaccination is not recommended, since at this time the fetus is very vulnerable to any influences.

The flu vaccine does not provide 100% protection against the disease, since there are many types and strains of pathogens, and the vaccine helps to acquire temporary immunity only to most of them (but not to all). Therefore, during an epidemic, a vaccinated person must observe the rules of personal hygiene.

Another common method of fighting the flu is taking antiviral medications. However, most doctors do not recommend using this method of prevention, because:

Most drugs are ineffective in low doses, and in high doses they can only be used for a short period of time, otherwise there is a risk of serious side effects;
Many flu remedies have questionable effects.

Therefore, it is not recommended to buy and take drugs to protect against influenza on your own. During an epidemic, products that enhance immunity and improve the general condition of the body will be better protected:

Vitamins

However, it is important to know that their excess is also harmful, so you should not take drugs in a larger dose than indicated in the instructions; Herbal tea made from lemon balm, linden blossom and hop cones; Garlic and onion. These plants contain phytoncides that kill influenza pathogens.

For more information about vaccinations, see the article: Who should get a flu shot?

Preventing Fever

To prevent your temperature from rising rapidly after a flu shot, you should follow some recommendations and generally know how to prepare for vaccination. These tips are especially relevant for young children, whose bodies react to such medical manipulations more sensitively.

2nd generation antihistamines, taken according to instructions for three days before the day of vaccination, and then 1 day after, reduce the risk of unpleasant consequences after the injection.
On the day of vaccination and for 24 hours after it, you can take an antipyretic drug, for example, ibuprofen. It is better for the child to put a candle with an antipyretic effect, for example, “Viferon”.
After vaccination, it is recommended to rest and lie down in a calm environment. It is better to create conditions for the child that will allow him to take his mind off the hospital visit and relax. It is better to replace studying, active play and sports with quiet games and reading books.
After vaccination, you need to monitor your diet, eliminating all allergens and new, previously untried products from the menu.

If a high fever does not occur within a couple of days after the flu shot, you can return to your normal activities.

How to deal with high fever

Regardless of what led to an increase in body temperature after immunization to 38 degrees or higher, certain measures must be taken. Do this with the help of the following antipyretic drugs:

Paracetamol in suppositories . The drug is approved for use by children aged three years and older. The action of Paracetamol is reduced to inhibition of the excitability of the thermoregulation center. After administering the suppository, the temperature drops to 36.6 degrees within 60 minutes, and the resulting effect lasts for four hours. Paracetamol price from 55 rubles;
Nurofen syrup . Allowed for use by children from three months to 12 years. This is an effective antipyretic drug. It is based on the non-narcotic analgesic ibuprofen. The temperature decreases after taking Nurofen due to a decrease in the concentration of prostaglandins in the thermoregulation center, which is concentrated in the hypothalamus. The cost of the medicine is from 114 rubles;
Nurofen tablets . The tablets have a composition similar to syrup. Their effect is not only to reduce fever, but also to eliminate pain. The medication is approved for children over 12 years of age and adults. The cost of the drug is from 97 rubles;
Ibuprofen tablets . This is the simplest and most effective analgesic. The positive effect is achieved 1 hour after administration. Take the drug for pain and high temperature of any origin. Tablets are allowed for children over 12 years of age and adults. The cost is 45 rubles;
Nimesil powder . This is an effective antipyretic drug based on nimesulide. It also has an analgesic and anti-inflammatory effect. Nimesil reduces the temperature for up to 6 hours, and its properties do not deteriorate with prolonged use. The drug is contraindicated for children;
Coldrex Hotrem . This drug for internal use is recommended for adults and children over 12 years of age. Use 1 sachet every 6-8 hours during the day. To prepare the solution, you need to dilute 1 sachet of the product in 200 ml of boiled warm water. You can add sugar. The maximum course of therapy is 5 days;
Theraflu . The drugs are prescribed 1 sachet orally. Dissolve the contents of the package in 200 ml of hot water. Take the solution hot every 4-6 hours. The daily dosage is 3 sachets. Take Theraflu for no longer than 5 days;
Rinzasip . This drug can be used by adults and children over 15 years of age. An interval of 4-6 hours should be maintained between doses. The daily dose is 4 sachets, and treatment lasts about 5 days.

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High fever from vaccination with complications

When a high temperature is observed in combination with additional symptoms such as nausea and headache, you should immediately consult a doctor. In addition to medications, you can reduce your temperature in the following ways:

Compress . It is necessary to soak a terry towel in mint decoction (20 g per 250 ml of boiling water). Wring out the napkin so that it is damp but not wet. Place the compress on the forehead, temple, and groin folds. Keep it for 10 minutes. This method can be used to lower a child’s temperature;
Wraps . To obtain the desired result, take a cotton cloth and support it in a water infusion of yarrow, and then apply it to the forehead and hold for 20 minutes;
Vinegar wraps . Combine vinegar and water in a ratio of 1:5 in a container. Soak a sponge in the solution and apply first to the back and stomach, and then to the legs and arms. Repeat such activities every 2-3 hours. This method is also suitable for small children;
Drink plenty and frequently . You can drink fruit juice, compote, tea with lemon. This is extremely necessary, since heat transfer occurs during the evaporation of sweat from the skin, as well as during breathing and urination. You need to drink a lot of fluid until the color of your urine changes from deep yellow to light yellow;
If a child has a fever after a flu shot, there is no need to wrap him up tightly. If the house is warm, then just wear a T-shirt and shorts. But you don’t need to bathe your baby, even if he’s hot.

Influenza vaccination is a process necessary for adults and children to protect the body from the disease or facilitate its progression. After a flu shot, the temperature may rise to 38 degrees, but it lasts no more than 1-2 days. If the temperature is high and additional symptoms occur, this is a reason to consult a doctor. Perhaps the reason for the elevated temperature is not vaccination, but the presence of a hidden disease that needs to be treated.

If you have a fever, what should you do?

If a fever does occur, it is necessary to assess the extent of the problem. Temperatures up to 37.5-38 degrees are absolutely normal. It indicates that the immune system is working well, is sensitive to viruses that enter the body and strives to quickly destroy them.

You can alleviate your condition in the following ways:

take paracetamol or ibuprofen (aspirin during fever is undesirable, especially for children);
wipe the body with a sponge and cool water, paying attention to the armpits, neck, inner and back of the thighs;
drink more fluids;
ventilate the room;
rest and sleep.

If after a flu shot your temperature is 39 or higher, you should immediately call a doctor. Most likely, after the examination, the doctor will prescribe antibacterial therapy based on the existing symptoms. There is no need to worry and think about the exceptional harm of vaccination. According to statistics, fever after vaccination in 6 out of 10 cases is a consequence of a viral or bacterial infection during the incubation period. That is, the disease would occur regardless of whether the person was vaccinated or not.

Therapy methods

The main method of treating pathology is taking special medications

It is equally important to organize a special daily routine for your child.

Regular events

Children suffering from complicated forms of swine flu are subject to immediate hospitalization.

If there is no risk of complications, the patient still needs a special regimen. In particular, throughout the entire period of fever, it is necessary to limit the baby’s physical activity; he should remain in bed.

It is important to ensure proper nutrition (the diet should consist of light foods that do not overload the digestive system; if a child refuses to eat, there is no need to force him). It is important to ensure adequate fluid intake

It is important to ensure adequate fluid intake. Warm drinks, herbal teas, still mineral water are recommended

This will help avoid dehydration, a life-threatening condition for the baby.

Warm drinks, herbal teas, and still mineral water are recommended. This will avoid dehydration, a condition that is life-threatening for the baby.

Medicines

In case of swine flu, the child is required to take antiviral drugs. For severe forms of the disease, drugs such as Tamiflu and Relenza are used.

For milder forms of the disease, Arbidol, Grippferon, Viferon are prescribed.

Depending on the clinical manifestations of the pathology, medications from the following groups can also be used:

Antibacterial drugs in case of bacterial infection.
Infusion detoxification agents and hormonal preparations of the glucocorticosteroid group for severe symptoms of body poisoning.
Rehydration medications for severe dehydration.
Glucocorticosteroids to ease breathing.
Antipyretic at temperatures above 38 degrees.
Vasoconstrictors for the nose with heavy flow.
Antitussives to ease mucus discharge.
Antihistamines to eliminate swelling of the mucous membranes of the nasopharynx and skin rashes.

When will the temperature drop?

If the body temperature has risen not due to the hidden course of other diseases, but was the body’s reaction to the serum, as a rule, it rises on the first day, can last the second day and return to normal on the third day.

That is, if a person complains that he has a high fever a week after getting a flu shot, it is highly likely that the fever and vaccination do not correlate with each other.

But there are exceptions to any rule, because each person’s body is individual.

Varieties of influenza

All types of influenza are divided into three serotypes: A, B and C. Within one serotype, viruses differ in the location of the hemagglutin and neurominidase proteins. The study of these structures revealed that the causative agents of seasonal influenza are a large group of viruses, among which there are representatives of all three serotypes.

But there are types of influenza that are especially dangerous for humans. These include:

Bird flu. It is very difficult for humans to tolerate and often leads to death. The infection is not transmitted between people - infection is possible only from sick birds;
Swine flu. Belongs to serotype C. The infection is transmitted by pigs and other animals. Mutated forms of this virus can be transmitted from one person to another;
Hong Kong flu. Caused by a mutated pathogen, it belongs to serotype A. Known since 1968.

In terms of the course of the disease, these forms differ little from ordinary flu, so doctors have developed a rapid test to determine the type of virus. However, the technique does not yet allow us to determine the specific strain of the pathogen.