The H1N1 virus, which had pushed Mumbaiites behind masks, is retreating. There is a drastic drop in the number of fresh swine flu cases and no death has been reported in the past two weeks in Mumbai.
According to experts, this could be due a combination of the October heat sapping the virus of its potency and Mumbaiites developing immunity to the virus.
Dr Abhay Choudhary, director of the Haffkine Institute at Parel, said the communicability of H1N1 virus has gone down as people have developed immunity to it. “Now most of us have been exposed to it and so the susceptible population has reduced,” he said.
BMC officials said only 254 people went for screening on Wednesday as compared to the 3,000-odd, who used to throng the screening centres daily after the city’s first death in August.
Dr Choudhary said the proportion of positive cases has dropped drastically. “Earlier about 40 per cent of the throat swabs sent to us would test positive for the virus. Now it is barely 10 to 12 per cent,” he said.
Civic officials had also sent a batch of 25 swabs to Haffkine last week to analyse the “positivity” of the virus. The reports of only two patients came positive. “This shows that the spread of the virus has abated,” said additional municipal commissioner, Manisha Mhaiskar.
Physician and infectious disease expert Dr Jehangir Sorabjee said the dry October heat could have weakened the virus. “Heat tends to kill off viruses,” he said.
State health secretary Sharvaree Gokhale said that by mid-November, they would be able to understand change in the virus behaviour. “We’ll have to watch out for more cases when the temperature dips,” she said.