H1N1 Swine Flu: Symptoms, Causes and Treatments

The H1N1 swine flu began in the United States in 2009 and soon spread to several countries around the world. Although the pandemic was averted, the virus is still circulating today, but the influenza vaccine can help prevent infection.
H1N1 Swine Flu: Symptoms, Causes and Treatments

Written by Edith Sánchez

Last update: 27 May, 2022

H1N1 swine flu, more colloquially known only as “swine flu”, is an infection caused by a virus. At first, specialists believed that this disease was similar to the influenza that occurs in pigs and had been passed to humans through frequent contact with these animals.

Eventually, it was discovered that the H1N1 swine flu virus actually combines elements of swine, bird, and human viruses. In 2009, an outbreak of this disease occurred and spread around the world which was the beginning of a pandemic.

By 2010, the World Health Organization (WHO) declared the end of the pandemic. However, the H1N1 swine flu virus hasn’t disappeared. It’s now considered to be a regular human flu virus and has not re-emerged. The flu vaccine can prevent this infection.

What causes it?

A woman with a cold.
This disease is easy to transmit.

H1N1 swine flu is caused by a particular strain of influenza. In the vast majority of cases, it’s transmitted from person to person and not from animal to person. It’s important to note that you can’t get this disease by eating pork, as some seem to believe.

Transmission occurs through saliva or mucus particles. It occurs when a person inhales contaminated droplets produced by coughing or sneezing from someone infected.

You can also get H1N1 swine flu when infected droplets land on a surface. If another person comes in contact with it and then touches their eyes, nose, or mouth, they can get the virus.

Risk factors of H1N1 swine flu

During the first outbreak of H1N1 swine flu, the most affected were children over 5 years of age and young people. This was unusual, as precisely these segments of the population are usually less vulnerable to the effect of viruses.

Currently, the risk factors for acquiring H1N1 influenza are the same as for any other influenza strain. So the greater the contact with infected people, the greater the chance of contracting the disease.

On the other hand, those who have a higher risk of complications are the following groups:

  • People over 65 years of age
  • Children under 5 years of age
  • Young adults and people under 19 years of age receiving long-term aspirin therapy
  • People with weakened immune systems
  • People with chronic diseases such as asthma, diabetes mellitus, heart disease, or neuromuscular disease
  • Pregnant women

Symptoms of H1N1 swine flu

Symptoms of H1N1 swine flu are very similar to those of regular flu. They may include one or more of the following:

  • Coughing
  • Sore throat
  • Stuffy or runny nose
  • Red, watery eyes
  • Headache
  • Body aches
  • Fatigue
  • Sometimes fever and chills
  • Diarrhea
  • Nausea and vomiting

As in the case of common influenza, this type of flu can also cause serious complications. Likewise, in some cases, it worsens the symptoms of pre-existing chronic diseases.

Possible complications of H1N1 swine flu

In young children, H1N1 swine flu infection can cause symptoms such as the following:

  • Shortness of breath or very fast breathing
  • Irritability
  • Bluish skin color
  • Lack of interaction or awakening
  • Severe cough and high fever
  • Rash

For adults, severe symptoms include the following:

  • Shortness of breath or difficulty breathing
  • Feeling of pressure or pain in the chest or abdomen
  • Sudden dizziness and/or confusion
  • Severe and continuous vomiting
  • Severe cough and high fever

The disease may lead to pneumonia, respiratory failure, severe neurological symptoms (such as seizures), or increased severity of chronic diseases such as asthma or heart disease.

Diagnostic Tests

H1N1 swine flu is very similar to seasonal or regular flu, so doctors must run tests to make an accurate diagnosis. In principle, a differential criterion is that in H1N1 there are usually more digestive symptoms, such as pain in the abdomen and vomiting.

However, the only way to prove swine flu is by laboratory analysis. For this, a health professional takes a mucus sample with a swab, which is a slightly larger version of the ones you have at home. Then, this sample is analyzed to determine the presence of the disease.

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Available treatments

Doctor with pills
Most of the treatment is symptomatic.

Currently, the seasonal influenza vaccine also protects against the H1N1 swine flu virus. It’s administered by injection or spray and is effective against the infectious agent.

If a person isn’t vaccinated, the disease can be treated with the same antivirals used to combat the common influenza. Their main effect is to reduce symptoms. In addition, they’re much more effective if this is done within the first 48 hours after detection of the disease.

On the other hand, if a person has the infection, doctors advise you get plenty of rest so that the immune system can concentrate on the infection. It’s also important to drink plenty of fluids to prevent dehydration and take painkillers to reduce discomfort.

Prevention and recommendations

The best way to prevent H1N1 swine flu is to get the influenza vaccine. You should get it once a year and doctors recommend it for everyone over 6 months of age. In older adults, this is even more necessary.

It’s also important to avoid contact with people who have this virus. If you become infected, it’s best to stay home and cover your mouth and nose when coughing and sneezing. Only go out 24 hours after the fever has subsided.

In general, you should wash your hands frequently and keep household surfaces clean, especially if someone is infected. Don’t touch your eyes, nose, or mouth with dirty hands.

Pregnant women, adults over 65 years of age, children under 5 years of age, or those suffering from a chronic disease should avoid contact with pigs, even at fairs or similar places.

A disease to watch out for

Viruses have always been a challenge for mankind. As in the case of H1N1 swine flu, they often appear suddenly and uncontrollably. Therefore, it’s best to turn preventive measures into lifestyle habits.

In conclusion, vaccines are an excellent tool to fight viruses. It’s best for everyone to have all vaccinations up to date and to keep all precautionary measures to avoid any type of contagion.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.