The deadly swine flu virus tightens grip
to a week after.
Influenza A (H1N1)pdm09 virus has been the predominant seasonal flu strain worldwide over the past seven years. But in 2017, the influenza A(H3N2) and B viruses became the predominant strains, said the WHO.
In India and the Maldives, influenza A(H1N1)pdm09 continues to be the predominant strain, with neighbouring Pakistan reporting sporadic cases of influenza A(H3N2) viruses in the recent weeks.
Flu peaks twice a year in India, in July and August and again from October to February. But cases are reported throughout the year.
Getting vaccination each year reduces symptoms, shortens the duration of the illness and lowers doctors’ visits and flu-related hospitalizations.
But people in India rarely get vaccinated against H1N1.
Each year, the WHO recommends a vaccine that targets the three most deadly flu strains based on flu-tracking data from 143 National Influenza Centres in 113 countries, including India. In the 2017 vaccine, the A/California/7/2009 (H1N1)pdm09 virus has been replaced with an A/Michigan/45/2015 (H1N1)pdm09 virus, while the other two viruses -- the A/Hong Kong/4801/2014 (H3N2) virus; and B/Brisbane/60/2008 – remain the same as last year.
The quadrivalent vaccine against four flu viruses includes the B/Phuket/3073/2013 virus.
Vaccinating people at risk is a must in regions where infection continues throughout the year and chances of death from complications are higher because of late diagnosis, undernourishment and poor health infrastructure.
In older persons, vaccination lowers influenza-related illnesses by 60% and deaths by 70-80%.
Among healthy adults, it reduces illness by 70-90%, and in children, cuts flurelated ICU admission by 74%.
“Now is a good time for people in India to get vaccinated against seasonal flu
On April 12, 2009, a new virus appeared in Mexico and triggered the first pandemic of the 21st century.
Initially called “swine flu” because the new virus shared genes with an influenza virus that infected pigs, it was renamed influenza A/(H1N1) pdm09 by the World Health Organization.
By June 2009, A/(H1N1) pdm09 caused 94,512 confirmed cases and 429 deaths across 135 countries.
Getting flu vaccination each year reduces symptoms, shortens the duration of the illness and lowers doctors’ visits and flu-related hospitalisations because it takes four to six weeks for the protective effects to kick in. Getting vaccinated now will protect people when the flu peaks during the monsoons and again in winter,” said Dr Krishan Chugh, director and head of pediatrics at Fortis Memorial Research Institute, Gurugram.
“Vaccination not just protects you from infection but also makes you less contagious and reduces the transmission of infection. As more people get vaccinated, the viral load in the community goes down and everyone develop ‘herd immunity’, which makes fewer people vulnerable to serious flu complications,” said Dr Chugh.
All inactivated influenza vaccines contain trace levels of egg protein and should not be given to people with egg protein allergies.
The antigenic shift from A/California/7/2009 (H1N1)pdm09 to A/Michigan/45/2015 (H1N1)pdm09 in 2017 is a minor change and has not led to drug resistance against standard anti-viral medicines used to treat the H1N1 or influenced viral entry into cells, transmission and tissue tropism (cells and tissues that host the virus in the body).
“The Michigan strain has been milder than the California strain in the US and with fewer deaths this year, the trend in India seems to be the same,” said a health ministry official who did not want to be named.
Oseltamivir and zanamivir, the antiviral drugs used to treat H1N1, lower the viral-load, shorten the duration and severity of illness and make the patients less contagious.
“Both medicines are manufactured in India and all states have procured drugs. The government does not stockpile the flu vaccine because its life is nine months to a year, but since it is also manufactured in India, there’s no shortfall,” said the ministry official.