An alarming rise in the prevalence of swine flu has occurred this year. As of the 9th July the H1N1 virus has affected 12,460 people and has been responsible for 600 deaths. This increase is considerable. Only 1786 infections occurred in 2016, with 265 deaths associated with the virus.
Experts are particularly concerned at the demographics that have been falling victim to this latest spread of swine flu. Flu is typically thought of as a disease which puts the elderly at risk, due to weaker immune systems, but this outbreak is disproportionately affecting those between the ages of 20 and 50. Around 40 percent of the deaths and 50 percent of the infections have occurred in this age range.
The state surveillance officer for Maharashtra, Dr Pradeep Awate, has suggested that the large number of younger people being infected may be due to their increased rate of travel compared to a more elderly group. This, combined with groups of young people gathering for work or in social situations presents ideal circumstances for the airborne flu virus to spread between hosts. Dr Awate’s state, Maharashtra, has accounted for 284 deaths so far this year. This alone is higher than the number of deaths last year in the whole of India.
The steep rise in the number of cases may be accounted for by a change in the strain or mutation of the structure. The strain may have mutated due to a process known as antigenic drift. This involves small changes in the genetic structure of the virus that alter the structure of antigens on the surface of the virus. This causes previous immunity gained from prior flu infections to be negated, and is the reason why vaccines must constantly be updated.
Antigenic drift may explain the reason why more deaths have occurred this year. Though partially explained by the higher number of infections, experts have also indicated a higher mortality rate in the infected. Dr Om Shrivastav notes that a typical mortality rate from seasonal flu varies between 0.5 percent and 1.5 percent. This year however the rate has increased to 4.5 percent.
The sudden rise, especially among the young, has baffled experts. One explanation has been that those that have died with comorbid conditions have been noted down as having exclusively died of the flu. Dr Awate considers the possibility of pre-existing conditions causing a vulnerability to swine flu infection “If the patient has other co-morbidities which has resulted in death, we cannot blame H1N1.” Though this explanation accounts for many of the deaths, it does not explain the sudden rise specifically amongst the young as the elderly would be more prone to comorbid conditions.
Some state health authorities have decided to proceed with an audit of all swine flu related deaths. These will reveal a more accurate idea of the death toll that can be associated purely with the virus, and how many died due to pre-existing conditions. This will give a better indication of the severity of this years flu season, though at the current time, this year’s outbreak of swine flu appears far more severe.