Influenza A (H1N1), commonly known as ‘Swine Flu’, is caused by H1N1 subtype of Influenza A virus. In 2009, World Health Organization (WHO) has declared the viral strain of swine-origin H1N1 as a pandemic. The infection shows similar symptoms to seasonal flu such as a sore throat, chills, severe headache, cough, weakness and gastrointestinal discomfort. Respiratory failure, rapidly progressive pneumonia, acute respiratory distress syndrome, pulmonary embolic episodes are the severe manifestations occurring during H1N1 infection. H1N1 is a multifaceted infection that affects not only lung parenchyma, but the involvement of pulmonary artery vessels is another important cause of fatality or severity.
The virus has affected numerous lives around the world in the recent past. The major notable worldwide incidents of H1N1 are: Fort Dix outbreak of 1976, Russian flu of 1977-78, Influenza A pandemic of 2009, India outbreak of 2015, and Maldives and Myanmar outbreak of 2017. India is among one of the most ruthlessly affected countries in the world. The post-pandemic period after 2009 reported 62,000 laboratory-confirmed H1N1 cases with nearly 5000 deaths. India outbreak of 2015, the disease affected more than 30,000 people and claimed over 1,700 lives.
The consequence of infections followed by death is enduring and India is facing an adverse and challenging scenario. In 2016, around 1,786 people had H1N1 infections with 265 deaths. As per Times of India news, the virus H1N1 affected 22,186 people and caused 1,100 deaths till September 2017 (Sep 2, 2017). This data indicates that the mortality rate is very high in India and warrant a national and state level programmes to develop advanced strategies against H1N1 pandemic. The present article is focused on the challenges India is facing to fight against H1N1, need of a vaccination programme in India, recommended target groups of vaccination, and special emphasis of vaccination in adults and healthcare workers.
Is the current strategy against H1N1 enough to face the challenges in India?
Oseltamivir and Zanamivir are the commonly recommended anti-viral drugs against H1N1. Several proprietary live attenuated vaccines are available for H1N1 with or without combination Influenza B vaccines. As per MedPlusMart online pharmacy these drugs/vaccines are available under various brand/proprietary names in the price range from Rs. 470-4000. The drugs were earlier put in schedule X to prevent misuse and overuse of the drug which could lead to drug resistance. The Indian Government currently reduced the restrictions on the sale of these anti-viral drugs to improve the distribution system of drugs.
Although many Indian pharmaceutical companies are continuously striving to avail the drugs/vaccines at cheaper rates, the high cost and availability of the drugs/vaccines represented a major challenge toward complete eradication of H1N1 from the country. Recent survey indicated that there is a necessity of health awareness programmes to spread the essential information on symptoms, mode of transmission and preventive measures in health care workers and different groups of people based on gender, age groups, educational status and working status.
Although mutation/s in the genetic sequence of the virus lead to drug resistance, a study during 2015 Indian pandemic revealed that there was no mutation/s in the viral strain and suggested the 2009pdmH1N1 pandemic strain A/California/04/2009 was responsible for the outbreak in India. Continuous tracking of viral evolution and predicting potential pandemic assists in the development of various remedial and preventable approaches. However, the monitoring system of influenza has not yet reached the adequate levels to enable real-time surveillance .
The cases of the H1N1 infection are reported throughout the year with two seasons as peak periods. A major peak period of infection occurs in rainy season during July-August, and a minor peak occurs winter-spring season during December-February. However, there was an unpredictability of Indian H1N1 influenza seasons in the recent past years.
Vaccination against H1N1 and recommended target groups
The vaccines for H1N1 are available in India under various proprietary names, such as, Vaxigrip, Nasovac, Agrippal, Fluarix, Influgen and Influvac. As per Ministry of Health and Family Welfare, H1N1 vaccine should be taken every year as the immunity lasts only for a year. National Institute of Virology, Pune, India advises a flu shot in the month of May to cover two periods of increased viral activity in Indian continent, considering the period required to develop immunity against the virus.
The Centre for Disease Control and Prevention, Atlanta, a U.S. based public health Institute recommends H1N1 vaccines to children between 4 months to 5 years; adults above 50 years who are suffering from chronic respiratory, cardiovascular problems, diabetes; pregnant women; and health care workers. Similar vaccination guidelines are provided by Ministry of Healthcare and Family Welfare, India. It recommends vaccine to four major groups: elderly individuals (?65 years) and children between 6 month to 8 years; pregnant women irrespective of duration of pregnancy; adults and children on medical conditions; and health care worker. National Institute for Communicable Disease of South Africa recommends a vaccine to those who wish to protect themselves from influenza.
Need of vaccination programme in adults especially healthcare worker
The major difference in seasonal and pandemic flu is that pandemic flu affects even the adults who had no risk factor or medical conditions, and the severity and mortality of pandemic flu is higher than seasonal flu . A report on 2009 pandemic revealed that H1N1 related deaths were 3.5, 1.1, 4.2 and 7.2 per 1,00,000 population for those aged 0-4, 5-24, 25-64 and ?65 years, respectively (Castrodale et al., 2009). Other reports on 2015 Indian pandemic showed the 47.60% of infection cases and 52.11% of deaths were in the age group of 26-50 years in Rajasthan; 48.6% deaths occurred in the 18-40 years of age group in Jaipur city during Jan-Feb (Malhotra et al., 2016; Sharma et al., 2015). During 2009-10 pandemic the high fatality rates were found in young age group of 13-45 year (Rana et al., 2012). Though there is need of systematic surveillance on age groups infected by H1N1, this information indicated that during H1N1 pandemic adults including high risk group adult were more vulnerable to infection.
There is higher chance of infection getting transmitted in health care workers. Although the burden of infection is substantial with moderate severity and fatalities, the effectiveness of vaccine and level of evidence are high in healthcare worker. The prioritization of vaccination to health care worker should be after high-risk associated groups (Vashishtha et al., 2013). Despite recommendation by Ministry of Healthcare and Family Welfare for vaccination in healthcare workers, the voluntary vaccination could give a little success toward eradication of virus.The high risk groups are generally covered under government vaccination programmes. Taking into consideration the pandemic scenario of H1N1 in India there is an emergence of a national level vaccination programme for adults as well. There should be a mandatory vaccination for all healthcare workers to prevent the spread and severity of H1N1.