H3N2 flu (influenza virus): symptoms, vaccine and prevention


What is H3N2?

H3N2 is a subtype of the influenza A virus , responsible for the largest flu outbreak in the United States in recent years, with more than 47,000 people infected. It recently arrived in Brazil and drew the attention of health authorities.

Originally, H3N2 is not a virus that affects humans, it is more common in species such as birds and swine. However, transmission between people is possible. Thus, it is known as variant virus.

The name H3N2 corresponds to the two types of protein on its lining surface, namely hemagglutinin (H) and neuraminidase (N).

In children and the elderly, the virus becomes more worrying, but it must be prevented by all people, especially those belonging to groups at risk of the disease, such as pregnant women, pregnant women, health workers and indigenous people, for example.

As it is a seasonal flu, the vaccination campaign is preparing to serve the population so that it is prevented during the months when the disease has the highest incidence, between May and September.

The symptoms of H3N2 are common to that of influenza A H1N1. It is a disease that has treatment and cure. However, it can present serious health complications and lead to death.

Read on to learn more about this virus and the risks it poses. Good reading!

Influenza A

Influenza A viruses, the etiologic agent of Myxovirus influenzae , are the only ones capable of causing frequent annual epidemics and, to a lesser extent, pandemics.

They are able to reach all age groups in a short period of time, a characteristic possible due to their great power of variability and adaptation.

Because it has genetic material of a fragmented nature, the virus undergoes several mutations during the replication phase. In this process, the surface proteins (hemagglutinin and neuraminidase) are modified.

The mutations that the influenza virus undergoes happen independently. As a consequence, a variant of the virus can pass through the population and cause the disease, since immunity is not prepared for a new strain.

Difference between H3N2 and H1N1

H3N2 and H1N1 are subtypes of the Influenza A virus, being the most prevalent in cases of the disease. In previous years, when there were reports of flu outbreaks, the cause was significantly caused by the H1N1 subtype.

Recently, the picture has changed and the number of cases of the disease has become much higher due to the H3N2 subtype. However, despite the numerous variations that these viruses can suffer, both are capable of causing major epidemics and deaths.

Therefore, the only difference is that they belong to different strains, that is, viruses of different strains that descend from the same type, in which they share morphological or physiological similarities.

It is important to know that H3N2, in recent years, has undergone antigenic changes and that these mutations can occur during a flu season.

These variations may lead to an update of the expected annual vaccine components. Because of this, even people who have been vaccinated can experience the flu and complications related to the virus.

Severe Acute Respiratory Syndrome

Severe Acute Respiratory Syndrome, or SRAG and SARS, is a transmissible respiratory syndrome caused by a coronavirus .

The symptoms are similar to those of the flu, but in this condition they are more severe. This is a disease that can also be caused by the H3N2 virus.

At SRAG, patients can recover within one to two weeks, without major complications. However, you need to be very careful with this condition. Some people can develop severe breathing difficulties, which can lead to death.

Patients with influenza who are feverish with temperatures above 38 ºC, cough and dyspnea, gastrointestinal manifestations, tachypnea, hypotension or any clinical, laboratory or radiological condition similar to that of bronchopneumonia are considered to be carriers of SARS .

How does the transmission happen?

Transmission of the H3N2 virus occurs in the same way as in H1N1. It happens, therefore, through direct contact with airway secretions , from person to person or through indirect contact with a surface on which the infected person deposited the virus.

In the respiratory tract of the infected, the viruses replicate in the columnar epithelial cells and the secretions are mixed. Through coughing, sneezing or talking, they spread through these small aerosol particles.

The virus enters our body through the mouth, eyes and nose. It can also happen through contact with objects of infected people or surfaces where the virus has lodged.

In this respect, it is important to be careful, as the virus can survive for 24 to 48 hours outside a living organism. Thus, it is essential to clean surfaces such as computer keyboards, door handles and shared tables at work.

Issues related to the environment also interfere with the transmission of the disease. In places where the relative humidity of the air is lower, the greater the chance of transmission of the virus, due to the dry climate.

When installed in the patient’s respiratory tract, the virus incubation period is very short, lasting between 1 to 4 days.

In general, transmission occurs from 1 day before the onset of symptoms to 7 days after the first signs.

Its transmission period, however, may vary according to the patient’s age and clinical condition. In children and the immunosuppressed, for example, this window can be much larger.

A single infected person is able to transmit the disease to a very large number of people and thus spread the virus and increase the risk of an epidemic.

Groups of risk

This type of virus can reach everyone, in general, but there are some groups that are classified as most at risk.

In Brazil, for example, there are some groups that should be vaccinated as a priority, according to the Ministry of Health. Find out which ones are:

Children from 6 months to 5 years

Children are at greater risk for communicable diseases, and influenza A is no different. They should always follow the vaccination schedule correctly so that they are protected from possible outbreaks of the disease.

This age group, specifically, is related precisely to this factor, where the doses of the vaccine against the virus begin.

Seniors over 60

People over the age of 60 should be advised to vaccinate to prevent viral diseases such as influenza A. In this range, considered a risk group, complications can be more serious.


Pregnant women should be more careful with the H3N2 influenza A virus, as this disease can cause major complications during pregnancy.

During this period, the body is undergoing several changes in the immune, circulatory and pulmonary systems. These factors make pregnant women more prone to the disease, taking greater risks in cases of infection, including the need for hospitalization and death.

In addition, it is not only the mother’s health that becomes more fragile, that of the baby as well. Thus, influenza can interfere with pregnancy, including complications in labor or premature delivery .

Postpartum women (up to 45 days after delivery)

For the same reasons that pregnant women are in the risk group for this disease, there are women who are in the postpartum period (puerperium).


All people who belong to the indigenous population, after 6 months of life, should receive the vaccine, according to health recommendations. They are considered a group at risk from the virus.

Public and private network teachers

Due to the direct contact with classrooms and with risk factors, teachers from public and private schools are included within the risk group for the disease.

Prisoners and prison staff

Due to the conditions of these prison environments, people become more prone to disease transmission. As influenza spreads through respiratory secretions, for these people this factor also places them as a risk group.

People with chronic diseases

People who suffer from chronic conditions, such as heart, kidney, liver, neurological diseases, diabetes , immunosuppression, obesity ; who have undergone a transplant; or if they have trisomies, such as Down’s Syndrome, they should be more careful with the virus of this disease.

The vaccine is the factor that most contributes to the reduction of complications and mortality suffered by these groups.

Health professionals or workers

People who work in hospitals or laboratories, who may have contact with infected people or with the virus, are within the risk group because they are more susceptible to the disease.

Not only doctors and nursing staff are included in the risk group, but also people who work in the care, reception, security and ambulance drivers, for example.

Symptoms of H3N2

The flu signs are not new to most people, but when it comes to influenza A, it is important to remember all the symptoms carefully, to prevent the subtype H3N2 and the already known H1N1.

Between these two subtypes, there are no major differences between symptoms. They have, in most cases, the same effects on the patient.

In the beginning, when the virus is still incubated, the patient does not feel the symptoms and does not know that he is infected. With the spread of the virus through the airways, the initial signs are manifested. This phase can take one to four days.

The main characteristic of the disease is the acute infection of the airways , with fever above 37 ºC and 38 ºC, being more frequent in children. Other early symptoms are muscle pain, headache and tiredness .

This symptom is more permanent during the infection, where there is a decline after 2 or 3 days of the temperature, normalizing around the sixth day of the evolution of the flu.

When the patient has an intense dry cough and a runny nose, his body is already at a more advanced stage in the fight against invading viruses. The act of coughing and sneezing is the body’s response to clean up this debris.

With the perception of these signs, it is possible to distinguish the flu from a common cold . Pain and fever are a sign that the body needs more fluids, as the attack of antibodies to viruses causes greater dehydration.

In this process, it is common for the urine to become darker and for the patient to feel less of a need to urinate.

Other symptoms present are:

  • Sore throat;
  • Excessive runny nose (rhinorrhea);
  • Joint pain (arthralgia);
  • Chills;
  • Discomfort;
  • Headache (headache);
  • Muscle pain (myalgia);
  • Dry cough;
  • Weakness;
  • Vomiting;
  • Diarrhea;
  • Fatigue;
  • Redness in the eyes (conjunctival hyperemia);
  • Hoarseness.

Given the possibility of being influenza A, it is essential that the patient does not ignore the listed symptoms. Many people end up having complications for not recognizing the signs as something important, interpreting them only as a common cold or flu.

In children, symptoms such as bluish lips and skin, dehydration, breathing with difficulty or very fast, drowsiness, irritability or fever with skin rashes, should be taken to the doctor immediately.

People, in general, should seek medical help in the face of symptoms such as vomiting, chest pain, shortness of breath, abdominal pain, dizziness or sudden confusion.

If suspicious, seek medical help to receive the proper diagnosis and never self-medicate .


The doctors who can help the patient are the general practitioner, infectious disease specialist and pulmonologist . Generally, the first contact will be with the general practitioner.

Basically, the diagnosis is made through a sample of secretion from the nasopharynx. Preferably, this sample should be collected during the first three days since the onset of the first symptoms.

In addition to the laboratory test to identify the presence of the virus, the doctor must also take into account the signs of the disease, such as high fever, the most common sign during the first days of the flu.

Is there a cure?

Yes , influenza A, of the H3N2 subtype, is curable. Despite having already caused major epidemics and significant numbers of deaths from the disease, the flu has treatment and can be prevented.


The main treatment of influenza is with the use of Oseltamivir phosphate-based antiviral. Within an ideal framework, it should be administered within the first 48 hours after the manifestation of the symptoms of the disease and with a confirmed diagnosis.

This early treatment reduces the chances of complications and mortality. Although some people may be resistant to the drug, it usually proves to be effective in the recovery of the patient, in which the majority shows improvement of symptoms within a week.

In addition to medication, which should only be done under medical guidance, the patient can take a few steps to improve symptoms:


If it is a communicable disease and leaves the patient with symptoms that impair their day-to-day activities, one of the ways to treat the disease is to remain at rest.

In addition to speeding up the healing process of your body, the infected person prevents the virus from continuing to circulate and spread. For example, if you suspect that you are infected, see a doctor and stay at home for a few days to fully improve and not run the risk of passing the disease on to others.

Drink plenty of water

Keeping our body hydrated is always important, but when we have the flu it is part of the treatment. When we moisten the secretions, we are making it easier to expel and eliminate the virus.

In addition, when the patient is dehydrated, the symptoms of the disease may become more intense, such as fever and sore throats.


During treatment, the doctor can guide the patient to use some antivirals to relieve symptoms and reduce the risk of complications.

The effect of medications is most effective when administered within the first 48 hours since the onset of symptoms.

Within this period, the effectiveness of the medications is 25% to 30% for reducing the duration of the flu and 40% for decreasing the severity of the symptoms.

After 48 hours, it is up to the doctor to analyze which medicine will be the most beneficial for the patient.

In some cases, in which the patient is not at risk of complications, it may be that no antiviral is recommended.

Medicines available for influenza can be found in oral, inhaled and intravenous medication options. Are they:

  • Amantadine ;
  • Rapivab;
  • Rimantadina;
  • Oseltamivir (Tamiflu);
  • Zanamivir (Relenza).


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Living together

Influenza is not a disease that spends a lot of time with the patient, so to speak. In healthy adults and children, for example, within 1 to 2 weeks there is already an improvement in the condition.

However, during those days, the symptoms are not at all pleasant. For the family, it also becomes a complication, as some precautions must be taken so that they are not infected by the virus.

Here are some tips to make this time better and safer for everyone involved:

Isolated room

People who have a communicable disease, such as influenza A, should preferably avoid sharing a room. This measure is not always possible, but if it is, prefer to use it.

This way, other people who share the same house as the patient will be safer. If there is more than one sick person due to influenza, they can share the same room.

In the case of children who have the disease at the same time, it is advisable to keep them in the same space until they are better. If only one of them is sick, it is best to keep them in separate rooms.

Wear mask

Wearing a face mask can help reduce the chances of transmitting the virus by 70%. It is one of the recommendations for the patient to avoid spreading it during this recovery period.

Follow medication treatment correctly

If after medical diagnosis, the use of antiviral drugs is recommended, follow the medical guidelines correctly. Write down the necessary times and doses.

Keep environments well ventilated

It is essential, in a home where there is a patient sick with influenza or anywhere, that the air is kept clean.

So, remember to leave windows and doors open during the day or whenever possible, for the air to circulate. In the room where the patient sleeps is also essential.

Stay hydrated

During a viral infection like influenza, our body loses a lot of fluid trying to defend itself from the invading virus. During treatment, drink plenty of water and watch for signs of dehydration.

Some signs of dehydration, in adults and children, are:

  • I cry without tears;
  • Less urine. In babies, it is important to note whether the diapers are wet less frequently or less heavy;
  • When pulling on the skin, if there is a delay to return to normal;
  • Dry mouth and eyes;
  • Fast heartbeat;
  • Irritated, low energy and sleepy children.

Control the fever

Fever is one of the most characteristic symptoms of influenza A. During treatment, it is important to follow medical recommendations and take medications correctly, so that it does not come back. For this, it is advisable to have a thermometer at home, to check the temperature.

In addition to medications, placing a wet, cool towel on the patient’s forehead can help make him more comfortable.


The prognosis of influenza A, in its subtypes (H1N1, H2N2 and H3N2) and in type B virus, causes similar clinical conditions. However, in cases caused by influenza A, the occurrence of infections and serious complications is higher.

In healthy adults and children, the infection lasts an average of 1 to 2 weeks, showing moderate consequences. In the elderly and people with chronic illnesses, the virus can be a major health threat.

In these groups, the virus can often cause viral and bacterial pneumonia and aggravate pre-existing symptoms.

Some studies carried out with patients infected with the H3N2 virus have shown that, compared to the younger population, the prognosis of the disease is less favorable for people over the age of 49 years, with serious complications being more common for this group.


When the patient does not receive the proper treatment, he may end up suffering some complications caused by the virus or by the instability of the immune system.

Complications are more prevalent in elderly patients, children and individuals with vulnerable health.

In this case, the condition of the patient infected with H3N2 may evolve into the following conditions:


Infection with this virus can cause primary and secondary viral pneumonia in the patient. When it happens primarily, the condition is due to the presence of the disease. In secondary cases, pneumonia has a bacterial cause.

In pneumonia, the patient presents as a symptom of high fever and body pain, especially in the chest area. In this condition, if you have an aggravated infection in the lungs.

When this infection, which can be caused by influenza or another secondary virus or bacteria, reaches the alveoli, the patient may experience difficulty breathing.

Pulmonary and cardiac diseases

The cardiac and pulmonary complications that the patient with the flu may suffer are associated with the worsening of the condition of pneumonia. With proper treatment, this disease should not present risks like this.

The patient should seek medical advice even in the manifestation of the first flu symptoms, such as high fever, to prevent his clinical condition from presenting this type of complication.

Febrile seizures

Young children usually present with symptoms similar to bacterial sepsis , such as high fever. About 6% to 20% of children hospitalized for influenza virus infection manifest this complication.

Other infections

Due to the low immunity that viral infection can provide in the patient’s body, his body becomes more fragile to other infections, being more common in people who already have clinical vulnerability and elderly people.

Bacterial pneumonias are more frequent, usually caused by the agents Streptococcus pneumoniae , Staphylococcus ssp . and Haemophillus influenzae.

How to prevent H3N2

The prevention of H3N2 is not far from what should be done to prevent common flu. Even in times of outbreak, it is possible to follow some steps to prevent this disease. Know the main ones:

Wash your hands thoroughly

It is important to keep your hands clean. Remember to sanitize them frequently, especially before any meal. When you are in an environment where it is not possible to wash them, try to use alcohol gel.

Especially in winter, carrying alcohol gel facilitates hygiene and helps prevent this and other diseases.

After coughing and sneezing, it is also important to wash your hands, so as not to spread the virus over the surface of objects.

Avoid crowded and closed environments

Avoiding crowded and poorly ventilated environments can help contain and prevent the transmission of the virus. Because of these conditions, these places become a risk factor for diseases communicable by respiratory secretions such as influenza.

At home, try to leave doors and windows open to improve circulation. In public transport, too. Even with low temperatures or rainy weather, prioritize collective health and always keep a gap for circular air.

Maintain a healthy diet

Having a healthy diet helps to strengthen our immune system. Consuming good amounts of vitamin naturally helps prevent the flu and has numerous health benefits.

Do not share personal items

Whether you have any of the symptoms or not, avoid sharing personal items that may be responsible for transmitting the virus, such as cutlery, glasses, bottles and plates.

Use disposable wipes and cover your mouth and nose when sneezing

In the face of flu symptoms such as coughing and sneezing, use disposable wipes for nasal hygiene. Also, always cover your nose and mouth while sneezing or coughing, so as not to spread the virus.

It is recommended to avoid touching the mucous membranes of the eyes, nose and mouth. When contact is made, adequate hygiene must be carried out.

Avoid contact with people who have symptoms

To prevent your health, it is important to avoid too close contact with people who have the symptoms of the disease. During treatment, one of the recommendations is that patients stay at rest and avoid contact with other healthy people so as not to run the risk of spreading the virus.

If someone close to you, such as a co-worker or study, has the symptoms of the disease, advise them to seek medical help and take a few days to rest.


Vaccination is the most efficient way to prevent the disease and to avoid complications. Annually, if there are vaccination campaigns to prevent influenza A.

Vaccines are made available both by private laboratories and by the Unified Health System (SUS). In private laboratories, the average price is 130 reais. For groups considered at risk, SUS should make the vaccine available free of charge.

In current campaigns, the vaccines offered are trivalent , that is, capable of protecting the patient against influenza A (H1N1 and H3N2) and influenza B, considered by the World Health Organization (WHO) to be the viruses of greatest epidemiological importance.

Considering how much this virus undergoes mutations, it is necessary to have an update of the vaccine every year, to meet the needs of the population at that time.

According to the WHO, the vaccine applied in 2018 will be according to the strains of the virus that are in circulation in the world, which includes H1N1, H3N2 and the influenza B virus.

The vaccine, therefore, is the result of the combination of viruses similar to the three types of strains.

Although the vaccination campaign focuses on the groups most vulnerable to the virus, it is recommended that everyone who can receive the immunizer, do so.

Who can take it?

All people can receive the vaccine, but for groups at risk, it becomes indispensable. According to the Ministry of Health, the following groups should be prioritized:

  • Children from 6 months to 5 years of age;
  • People over the age of 60;
  • Pregnant women;
  • Health workers (doctors, nurses, hospital receptionists, security guards, etc.);
  • Indian people;
  • Postpartum women (up to 45 days after delivery);
  • Prison system officials;
  • Prison population;
  • Public or private network teachers;
  • People who have any clinical condition or chronic non-communicable disease (diabetes, obesity, transplant, kidney, liver or heart disease, patients with trisomies).

Side effects

The possible side effects of the vaccine are divided into two types: local and systemic. They include the following symptoms:

  • Pain at the site;
  • Redness of the skin (erythema);
  • Fever;
  • Discomfort;
  • Muscle aches;
  • Hypersensitivity reactions.

Local manifestations, such as pain at the site and redness, are signs considered benign. They happen between 15% to 20% of patients and it tends to disappear within 48 hours after application.

Signs such as fever and malaise, identified as systemic reactions, can occur between 6 hours to 12 hours after the vaccine and remain for up to 2 days.

Within that time, if the symptoms do not improve, the patient should seek medical advice. They are not common side effects, being recurrent in 1% of patients who receive them, usually when referring to the first contact with the vaccine.


The influenza vaccine had the contraindication to be avoided by people with a history of severe allergy to egg protein.

However, according to new recommendations from the Center for Disease Control (CDC) and the Advisory Committee on Immunization Practices (ACIP) in the USA, it is possible that these people will be vaccinated.

These guidelines, proposed in 2016, pose certain conditions for allergy sufferers to receive vaccination safely.

  • People allergic to egg protein who have urticaria can receive the influenza vaccine, without any attention different from that of other patients;
  • People allergic to egg protein who have symptoms other than urticaria, such as dizziness, frequent vomiting, angioedema, difficulty breathing, who may need adrenaline or any type of emergency medical intervention, can receive the vaccine as long as it is applied in a hospital, with medical supervision available.

With these new recommendations, it appears that it is no longer necessary for people allergic to the egg to remain for 30 minutes in observation, as in the old procedure.

However, as is recommended for all types of injectable vaccines, which can cause dizziness in the patient, all people must remain under observation for 15 minutes, until they are released.

People who have an allergic reaction when receiving the first dose are also considered within the group of contraindications and should not receive the vaccine again.

Therefore, it is worth remembering that even with the new review on vaccination for egg allergies, it is necessary to be careful and correctly follow the entire procedure.

The vaccine should also not be applied to children under 6 months of age .

Vaccination campaign 2019

In Ceará alone, until the beginning of March, 3 cases of H3N2 flu were registered, with others under investigation.

The 21st vaccination campaign referred to takes place between April 10 and May 31, and on May 4 the so-called D-day takes place , which is a national mobilization aimed at vaccinating the greatest number of people recommended.

Every year, vaccination undergoes adaptations to fight the agents of greater circulation. This year, there were 2 changes compared to last year, and the trivalent vaccine is composed of the strains:

  • A/Michigan/45/2015 (H1N1) pdm09;
  • A/Switzerland/8060/2017 (H3N2);
  • B / Colorado / 06/2017 (line B / Victoria / 2/87).

Common questions

The H3N2 virus is still little known among people and, with the possibility of outbreaks, causes great curiosity and concern about the subject. Check out some frequently asked questions:

Can the disease be transmitted by eating pork or other by-products?

No , it is not possible to transmit in this way. Although many people fear eating pork, in the face of an epidemic like this, meat that reaches consumers does not present a risk of contamination, due to two main factors.

The first is the sanitary inspection of the products, which must be carried out during the entire production process of this meat.

Another issue is that even if the animal was contaminated, after cooking at 70 ºC, no virus present in the raw meat would survive. Therefore, there is no need to fear this transmission.

When does the vaccination campaign take place?

The vaccination campaign against influenza A takes place annually, between the months of April and May .

The virus circulates throughout the year, but becomes more frequent during the fall and winter seasons, when temperatures drop. In the South and Southeast regions of Brazil, the spread of the virus becomes even more common.

The vaccine, in these months, is strategically capable of promoting greater immunity, because during this period people flock to environments and there is not so much air circulation due to more closed doors and windows.

After vaccination, it is possible to identify protective antibodies against influenza within 2 to 3 weeks. The body remains protected for about 6 to 12 months. Thus, annual vaccination is necessary to reduce the chances of complication of the disease.

Why should the vaccine in newborns be given only after 6 months?

The influenza A vaccine should only be given to babies after 6 months of age because pregnant women are part of the risk groups as well, so they also receive a vaccine.

Thus, the vaccine protects the mother, the fetus and the newborn until the age of 6 months.

However, if the mother suspects that the baby or herself has one of the flu symptoms, it is recommended to seek medical help for a diagnosis.

Do all people who receive the vaccine have the same degree of protection?

No, despite the fact that vaccination is 50% to 85% effective, its degree of protection can suffer different changes from person to person, as it is associated with several factors such as age, previous exposure to the virus and antigens.

Can I end up getting the flu when I get the vaccine?

No, there is no such risk. By using the inactivated virus, the vaccine is not a danger to healthy people and can be carried out without this concern.

Can breastfeeding women receive the vaccine?

In general, women who are breastfeeding can receive the vaccine, there are no contraindications that confirm any risk to the group. However, each case must be assessed individually.

Can women who receive the medicine to treat the disease continue to breastfeed?

Yes, there is no evidence that influenza antiviral medication affects or has side effects for women who are breastfeeding or for babies.

Does the influenza vaccine cause fainting?

Yes, some people may experience fainting (syncope) when receiving some type of injectable medication. To prevent the patient from having an accident, he must remain in the hospital for at least 15 minutes, under observation. After that brief period, if everything is fine, he is released.

Why is it necessary to receive the influenza vaccine annually?

The influenza vaccine must be performed annually as its effect guarantees protection for a period of 6 to 10 months. Thus, it is necessary to receive a new dose every year.

In addition to the time of effect, this periodicity is related to the high mutation rates of the virus, which occur during the replication phase. With these variations, the population becomes unprotected, because their immunity, even having received previous doses, is unable to recognize the new subtype.

These virus mutations happen annually and it is because of this cycle that epidemics happen. That is why it is so important to carry out vaccination campaigns every year and to update the vaccine components for the strain that are circulating among people.

Does the vaccine interfere with the results of other tests?

Yes, it does. People who received the influenza vaccine, whether fragmented or inactivated, may have the result of some laboratory tests for viruses with altered results, such as tests for the HIV -1, hepatitis C and HTLV-1 viruses .

When performing some laboratory tests like these, it is up to the patient to inform health professionals about the influenza vaccine received.

Can the influenza vaccine be applied simultaneously with vaccines for other diseases?

Yes, vaccines for the prevention of the influenza virus can be administered together with the other vaccines in the vaccination calendar, this in any age group.

Are vaccines administered intramuscularly?

Yes, the vaccine against influenza A, quadrivalent or trivalent, is administered intramuscularly. Patients suffering from a blood disorder may receive the injection subcutaneously.

Every year, we face seasonal flu seasons, and this year, a little-known virus has been on the agenda. H3N2, a subtype of influenza A, must be prevented and treated as a serious health hazard.

Watch for symptoms and seek medical help as soon as possible. With treatment, the patient should be well within a few days. However, without proper care, this flu can cause serious complications or even lead to death.

Keep a routine of preventive care and don’t forget to share this text so that more people can have access to information about this virus!