New virus, more outbreaks

A look at state-wise data shows that states with larger numbers of fatalities are also those with less successful public health infrastructure as a whole

In July 21, 2009, 14-year-old Rida Sheikh returned from St Anne’s School, Pune, with a runny nose and a headache. A quick trip to the neighbourhood physician later, she was back at school the next day. Five days later, she was on antibiotics. Three days after that, she was in the ICU on ventilator support. On July 30, her throat swabs were sent to National Institute of Virology. On August 4, swine flu had claimed its first recorded Indian victim.

Close to six years later, the Influenza A (H1N1) 2009 virus has killed 4,407 Indians according to officially recorded numbers. The extent of its spread is, however, far wider.

One of the reasons the virus has captured public imagination is that it is incredibly infectious. In research led by the World Health Organisation and Imperial College and published in 2013, Maria D. Van Kerkhove and her colleagues estimated that one-fifth of the population in 19 countries including India were infected with the virus in 2009-10, the first known season of the virus after the first case was discovered in Mexico in April 2009. The first official case in India was a 23-year-old man who flew into Hyderabad from the United States on May 19, 2009, and was screened at the airport.

The WHO declared H1N1 swine flu a pandemic in June 2009 when laboratories had identified cases in 74 countries, and only declared the pandemic to have ended in August 2010.

The fatality rates from swine flu however, are low; Ms. Kerkhove and her colleagues’ study estimated it at 0.02 per cent of all cases, meaning that only two out of every 100,000 people infected with swine flu died in 2009-10. These fatality ratios are lower than that of seasonal influenza, though public health experts warn against comparing a newer and less well-surveyed virus with seasonal flu.

Younger targets

Swine flu also disproportionately affected young children and younger people, leading to a larger loss in human years than seasonal influenza.

Officially, the world is in a “post-pandemic period” when it comes to swine flu. “Based on knowledge about past pandemics, the H1N1 (2009) virus is expected to continue to circulate as a seasonal virus for some years to come. While the level of concern is now greatly diminished, vigilance on the part of national health authorities remains important. Such vigilance is especially critical in the immediate post-pandemic period, when the behaviour of the H1N1 (2009) virus as a seasonal virus cannot be reliably predicted,” the WHO said in August 2010, declaring the end of the pandemic.

The threat from swine flu to India now needs to be viewed differently, health experts say, with the virus now settling into what is closer to a seasonal influenza pattern. India had 3,037 cases of swine flu and 275 deaths this year as of Saturday, Dr. Jagdish Prasad, Director General of Health Services, told The Hindu. Rajasthan was proving to be of greatest concern with 497 cases and 73 deaths as of Saturday, Dr. Prasad said, adding that a team had been sent to the state. “It does seem like the virus is settling into a seasonal pattern. As temperatures rise, the number of cases has begun to decline,” he said.

Better monitoring

With more deaths in just over a month than there were in all of 2014, it isn’t yet clear if the virus is spreading faster or if there is better surveillance, or if both are happening, Dr. Manish Kakkar, Senior Public Health Specialist, Communicable Diseases, at the Public Health Foundation of India, said. “Since this is a relatively new virus, we are likely to see outbreaks for several years before it settles down into a seasonal pattern,” he said. “But it is also true that before the pandemic, India never had influenza surveillance in place. There was very little laboratory work, very little data gathering and we weren’t investing much,” he said.

With better monitoring, the number of fatalities should decline as well. A look at state-wise data shows that states with larger numbers of fatalities are also those with less successful public health infrastructure as a whole. “Look at Delhi. It has 706 cases but only five deaths. If detected early, there should be no mortality,” Dr. Prasad said.

The government has begun testing a vaccine, but when it is ready for roll-out, it will be administered only to health workers and high risk individuals, Dr. Prasad said. Influenza vaccines are typically kept for high-risk groups only, and changes in the composition of the vaccine need to be made on a yearly basis, Dr. Kakkar said. “Moreover, there have been several studies showing that the effectiveness of the seasonal flu vaccine in many western countries is extremely low,” he cautioned.