All You Need To Know About H1N1

All You Need To Know About H1N1

It took only 3 months for the dangerous Influenza A H1N1 virus to spread around the World. That is why the World Health Organization declared it as a pandemic in June 2009, just 3 months after the identification of the virus. In 2013, India has reported 5253 cases of Influenza A H1N1 out of which 699 people died, a case fatality rate of 13.3%. Newer cases of Swine Flu are being diagnosed every day in our country and we need to know something about this virus in order to fight the deadly illness spread by it. In this article, I will be introducing you to the dangerous H1N1 virus, so keep your Masks ready!


Image Courtesy – Eneas De Troya

Swine Flu Transmission

As the word suggests, Swine flu or Pandemic Influenza A (H1N1) 2009 is primarily a flu of the pigs which is caused by a virus which has been identified as an Influeinza virus. The disease spreads from pigs to pigs and from pigs to humans when humans comes in close contact with the infected pigs. Human to human transmission happens through droplets which are released by an infected person when he coughs or sneezes. The high transmission factor among of this virus is one of the main reason why this disease has become a global pandemic within a very short time.

Signs and Symptoms

Symptoms of an “Influenza Like Illness (ILI) are seen in Swine Flu as well. This includes Fever, Upper respiratory symptoms, sore throat, cough. Headache, body ache, fatigue, diarrhoea and vomiting have also been observed.


Category A :
Mild fever + Cough/sore throat with or without body ache, headache, diarrhoea, vomiting

Category B1 :
Category A + high grade fever and severe sore throat

Category B2 :
Any mild Influenza Like Illness in high risk groups like Pregnant women and Children having predisposing risk factors (on steroid therapy) , old age (>65 years) etc

Category C :
Breathlessness, chest pain, drowsiness, fall in blood pressure, haemoptysis (coughing up of blood) and worsening of underlying long lasting illnesses.

H1N1 Testing

Category A : No testing required
Category B : No testing for categories B1 and B2
Categroy C : Testing may be needed. but usually test results are not required to start treatment.

If testing is indicated, contact Hospital nodal Medical Officer or District Surveillance Officer (DSO) or District Medical Officer.

Sample required : One threat swab + one nasal swab. In patients with lower respiratory tract symptoms, tracheal and bronchial aspirates are taken as samples. Samples taken should be immediately put in  Viral Transport Medium (VTM) and sent to the testing centres after proper refrigeration or by following “Cold Chain” principles.

Testing Centres : Testing centres in and around Kerala are as follows –

  • Rajeev Gandhi Centre for Biotechnology, Trivandrum
  • National Institute of Virology, Alapuzha
  • Virology division, KMC Manipal



The main line of treatment is with the anti-vital drug called Osaltamivir (TamiFlu)
For Category A – no Osaltamivir required. Symptomatic management like plenty of warm nourishing oral fluids, good food intake, complete bed rest are usually advised. Progress of the patient is monitored carefully and a reassessment is done after 24 hours – 48 hours.

For Category B1 – Supportive care as mentioned above should be given. Home isolation of the patient should be done and Osaltamivir has to be started.

For Category B2 – Start Osaltamivir immediately. Self isolation at home is also required. Telephone follow up is done for the next 2 to 3 days. If the person’s condition deteriorates, hospital admission might be necessary.


For Category C – Strict hospitalisation is required. Osaltamivir is started immediately without waiting for the test results. Intensive supportive management is also usually necessary in this category.

H1N1 in Pregnancy

Pregnancy is an extremely high risk category. Any Influenza like Illness in pregnancy whether it occurs before or after the delivery of the baby has to be suspected as H1N1 and Osaltamivir has to be started immediately. Early referral to appropriate centre had to be done in such cases. Osaltamivir has is considered safe in pregnancy.

Simple Measures to Control Infection

It has been found that the H1N1 virus transmission takes place in a way which is very similar to the other Influenza viruses. Proper infection control measures should be followed strictly and thesy include the following :-


  • Proper Technique Hand Washing with soap and water, sanitiser
  • Cover mouth and nose with tissue or handkerchief when coughing or sneezing
  • An infected or ill person should strictly wear a face mask if he/she is going to public places
  • For medical personals who are involved in high risk procedures like bronchoscopy should use a particulate respirator (N95, FFT2 or equivalent), eye protection, gown, gloves etc
  • Isolation of the affected person should be done at the appropriate centre
  • Warm saline thrat gargling and cleaning each nostril with warm water has aleo been found helpful in printing the spread of the virus.


H1N1 Vaccines

Both inactivated and live attenuated vaccines are available against Swine Flu. Inactivated vaccine is administered as single dose intramuscular injection in the upper arm. Pandemic influenza vaccines doesn’t give cent percent immunity against the disease, but they do help in greatly reducing the risk of the disease. Influenza vaccine only becomes effective only about 14 days after vaccination. Live attenuated vaccine are given via a nasal spray. WHO recommends that all the countries should immunise their Healthcare workers as a first priority.

Curative Approach to Swine Flu


  1. To clinically or diagnostically screen influenza like illness
  2. Categorize into A, B and C categories
  3. Home isolation for Category A and B
  4. Hospitalisation for Category C
  5. Treatment with Osaltamivir indicated for Category B and C
  6. Chemoprophylaxis for the family members, and other close contacts of positive cases
  7. No mass prophylaxis is advised


Post Endemic Period

We are currently in the post endemic period of this Influenza. Though the imminent danger of another outbreak is unlikely, the risk of the Influenza continuing as a seasonal illness is more in the current era particularly in the young children. The Government has still to be vigilant and keep the surveillance activities for the disease active for a long time to come. As part of the community we have our own role to play and we can start by following the steps mentioned in the “Simple measures to control infection” above.

Getting advice, opinions and prescriptions from doctors is now easier than ever before! You can chat, audio call or video call a doctor sitting in your home or office anytime. All you need is the Dofody App

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