India has recorded an alarming spike in swine flu (H1N1) this year, with 6,701 cases and 226 deaths confirmed till February 3, compared to 798 cases and 68 deaths during the corresponding period in 2018.
The sharpest spike was in the week ending February 3, which reported close to a third (2,101) of the total cases. Rajasthan alone confirmed 507 cases and 49 deaths in one week, followed by Delhi with 456 cases, shows data from across India (except West Bengal, which last sent updated data on August 18, 2018).
Delhi has reported no deaths.
In 2018, India confirmed 14,992 H1N1 cases and 1,103 deaths (this includes partial data from West Bengal), according to the Union health ministry’s Integrated Disease Surveillance Programme. Rajasthan had the highest number of cases, followed by Gujarat.
“Flu outbreaks are cyclic and the numbers go down every alternate year as outbreaks lead to the community developing immunity against infection. Last year, there were fewer than 15,000 cases, so this year we are expecting some increase,” said Union health secretary Preeti Sudan.
“The weather pattern is changing and this season, the cold has lasted longer. Cases in Delhi and Haryana have gone up, but there have been fewer deaths, which is an indication of good case management as 75% deaths occur in people at risk with co-morbidities, such as existing respiratory disorders, diabetes or high blood pressure,” Sudan added.
The health ministry has begun fortnightly video-conferencing with states, with a team from the National Centre for Disease Control working closely with Rajasthan to contain infection through a statewide campaign to diagnose and monitor all cases of fever, especially in rural areas where awareness is low.
Union health secretary Preeti Sudan held a high powered meeting with the senior ministry officials to review the preparedness and action taken to deal with spike in H1N1 cases on Wednesday. Some of the measures included enhanced surveillance across states and support for diagnostic tests.
Seasonal influenza, including H1N1, infects 3 to 5 million people worldwide and kills between 290,000 and 650,000 of them each year, estimates the World Health Organisation. In most cases, it causes symptoms of headache, fever, runny nose, cough and muscle pain, with people remaining undiagnosed and recovering within a week after using non-prescription medicines for fever and pain.
The seasonality of influenza is highly varied across India depending on latitude and environmental factors, shows data from past outbreaks. Influenza peaks in Srinagar from January to March, and in Delhi, Lucknow, Pune, Nagpur, Kolkata and Dibrugarh from July to September. Chennai and Vellore showed infection rising in October-November, coinciding with the monsoon months in these cities.
“For maximum protection, people in Srinagar should consider vaccinating in October and November, but people in the Gangetic plains and central India should vaccinate in May and June, and the southern states in August,” a scientist with the National Centre for Disease Control said on condition of anonymity as he is not authorised to speak to the media. The worst outbreak in Delhi was in the year 2010 when 77 people died of the viral infection out of 2725 who had tested positive.