H1N1 may become the main seasonal flu

Will the swine flu — H1N1 influenza — epidemic in India accelerate or decelerate in 2010?

The good news from virologists who are mapping the spread of the flu is that there could be a lull over the next two months as winter eases off. On the other hand, come June, when weather conditions improve for the growth of the virus, there could be another spike in swine flu cases.

What is imponderable is whether the virus will return in a mutated and more lethal form. Equally interesting is the probability that H1N1 could become the main strain of the influenza virus in India, replacing the seasonal flu.

Public health experts in Delhi say the H1N1 virus will replace seasonal influenza over a period of time. “This virus will affect a large population and eventually replace the common flu. After all, the common flu is also the same virus having different strains,” said RP Vashisht, a public health expert with the Delhi government.      

According to AC Mishra, director of the National Institute of Virology in Pune, hot weather conditions in most parts of the country in February and March will reduce the incidence of the flu.

“However, from June, 2010, the country could once again witness a rise in cases since weather conditions would be conducive for the virus. We have to keep a tab on the severity of the virus during that phase,” Mishra said.

Although some countries like China, Ukraine, England, USA and Brazil have reported a second wave of swine flu, India is unlikely to be hit by a second wave. “Even in countries which have been hit by a second wave, the virus is not virulent. The severity of the virus is more or less the same and a high pathogency (disease-causing agent) has not been noticed so far,” Mishra said. He predicted that there would be no second wave in India although the country could witness mini-waves.

The official figures from Delhi show that till December 31, 2009, there were 26,039 confirmed swine flu cases and 967 deaths. These numbers are obviously understated, since many thousands of cases may have gone unreported. The actual numbers could be double or triple the official figures.

Till date, samples from 1,12,766 persons have been tested for H1N1 in government laboratories and a few private laboratories across the country. About 77% of the total cases in India have been reported from 15 cities and health experts said the virus is slowly percolating to smaller cities.

The wave that had risen from Maharashtra, Karnataka and Tamil Nadu due virus-infected international travellers is now concentrated in the northern and central parts of India due to cold climate conditions. Though over 10 million passengers have been screened at airports, the fresh infections are now more in indigenous form.

Health experts say the H1N1 virus has struck different cities at different times, making its containment easier. They are also happy that the Indian population is developing immunity faster than expected.  “Going by the latest trend, the best part is that many of the persons are asymptomatic. Which means Indians are developing herd immunity faster and this will help in controlling the virus,” said VM Katoch, director general of Indian Council for Medical Research (ICMR).

“The virus has behaved very mildly across the world. Its mortality rate is only three-to-four times higher than the seasonal influenza, going by the 0.4% mortality rate seen so far globally. This is a self-limiting virus, just a variant form of common flu, and doesn’t last for more than 10 days in a person’s body,” Vashisht said.

However, the World Health Organisation (WHO) has stressed the need to guard against complacency. WHO director-general Margaret Chan said the virus was still active in some countries, including India and Egypt, and could mutate into a more dangerous strain. “It is too premature and too early for us to say we have come to an end of the pandemic influenza worldwide. We will watch this virus with eagle eyes,” Chan said.

A plus factor is that swine flu has made the Indian population more hygiene conscious. Since May, when the virus entered India, coughing and sneezing in public without covering the mouth has become less acceptable. Social life was also impacted in the early days of the fear psychosis, when people avoided closed spaces like restaurants, cinema halls, and malls.

The virus tested the public health system of the country, its rapid response teams and the disaster management system. By the time Indians adjusted to the virus, many deaths had already happened. “These deaths could have been prevented through a robust rapid response team that states like Delhi have put in place. Delhi has managed to keep the deaths very low due to a good home tracking system, preventive care and high awareness level,” a health ministry official claimed.

In 2010, epidemiologists and administrators are keeping their fingers crossed. “There should not be a severe mutation of the virus and it should stay as mild as possible,” said Katoch. And yes, vaccines will come in by March. Hopefully.