Influenza A (H1N1) pandemic, which took the world off guard in 2009, continues to be a major public health hazard and causes many deaths every year, especially in the vulnerable group. In the post pandemic period, there were two major outbreaks in 2015 and 2017, with lesser cases being reported in the intervening years. Influenza viruses have a tendency to re-assort themselves by exchanging genetic material with viruses from other hosts such as pigs, birds, etc and thus transform into a completely new virus which has pandemic potential. Swine flu (A (H1N1) pdm2009) , which was so called because some of the genes were derived from pigs is now being seen regularly as a
There are peaks in winter like any other flu virus and higher number of cases are also seen during the monsoons.
Most cases result in mild illness, like any other flu and the patient may respond without treatment. The risk of progression to severe disease and of dying is significantly greater in certain high risk groups such as the elderly, very young children, pregnant women, those with underlying illnesses like uncontrolled hypertension, diabetes, heart failure, respiratory conditions, obesity, kidney disease, etc.
Cases of H1N1 have been categorized by the Government of India, based on the clinical severity and the underlying co morbidities and the management protocol has been outlined. Mild cases do not need testing or treatment. Patients with more severe symptoms need testing and if required treatment, as deemed appropriate by the physician, based on the symptoms and the associated conditions. Such patients with mild and moderate illness, should confine themselves at home and avoid mingling with the public and high risk members in the family till the fever and cough resolves. Patients who are severely breathless, have chest pain, blood in the sputum, bluish discolouration of the nails or a worsening of the underlying illness such as a cardiac condition, need testing, immediate hospitalization and treatment. Antiviral treatment, wherever indicated, has to be started within 48 hours of the onset of symptoms, for it to be most effective. 2009 H1N1 influenza virus spreads from person to person through close contact in ways similar to
other influenza viruses such as inhalation of respiratory droplets during coughing, sneezing or singing. Touching a surface that is contaminated by the secretions of an infected person or shaking hands, may transmit the virus. Respiratory secretions, diarrhoeal stools and all bodily fluids are considered infectious. The period of infectivity usually lasts from 5-7 days from symptom onset and subsides with the resolution of fever and cough. This period of infectivity may be prolonged in severe cases, children and those in the high risk groups. Hence, it is important to follow cough etiquette i.e covering the nose and mouth during sneezing and coughing. A minimum distance of 6 feet must be maintained from infected individuals. Hand sanitizer should be used liberally, especially during the flu season.
Even simple hand washing with soap and water is effective. Avoid touching eyes, nose or mouth to prevent spreading of germs. Travelling should be avoided when sick, for a minimum of 7 days. Vaccination is recommended for all individuals older than 6 months of age, especially those belonging to the high risk group and their immediate contacts. Both injectable vaccine and the nasal spray (cannot be taken by pregnant women and certain other groups) are available. However, the physician should be consulted for the age appropriate vaccine. Very mild adverse effects may beobserved occasionally. Two weeks are required for the production of protective antibodies. The vaccine offers only 70-80% protection as it includes only 3 or 4 strains, out of the multitudes of flu strains which are circulating. A person may get flu even after vaccination, as the levels of protective antibodies decline over time, especially in the elderly and those with other co existing illnesses. Secondly, the flu may be caused by strains not included in the vaccine and also the infection may have occurred during the two weeks that it takes for the production of antibodies. Annual vaccination is recommended, as different strains are included every year, based on studies predicting the most likely strains that will be circulating.
Simple precautions like hand hygiene and cough etiquette will go a long way in preventing this potentially fatal infection.