H1N1 virus, dengue: ‘No need to panic, diseases can be controlled; community involvement crucial’

D T Mourya, director of the National Institute of Virology, along with his team, at the Idea Exchange at The Indian Express office. (Express Photo by Sandip Daundkar)

ANURADHA MASACARENHAS: Let’s talk about H1N1 first. The Influenza A H1N1 pandemic occurred in 2009 and since then we have been told there is immunity among people. Still, every year, there are so many cases and deaths.

DR MOURYA: The virus keeps evolving and while herd immunity is there, no one has really studied how long the immunity lasts after the natural infection. Studies need to be taken up by following a set of people who have been vaccinated. The California strain of this virus was prevalent so far, but from 2016, there has been a change in clade (genetic make-up of the virus) known as Michigan strain. So, even those who have been infected with the California strain can get the disease due to the change in the clade. This year, that is the reason we are seeing more cases. A vaccine does not ensure lifelong immunity.

ANURADHA MASCARENHAS: However, there is a lot of reluctance in getting vaccinated against H1N1 virus. What is the reason?

DR CHADHA: Since the Influenza A H1N1 pandemic in 2009, we have had a vaccine and an anti-viral therapy. When you take the vaccine not only are you preventing H1N1 but also H3N2, which is also Influenza A and can cause equally severe illness, and Influenza B. Now, we have a quadrivalent vaccine that takes care of both lineages of Influenza B. However, there is a lack of awareness and trust about this vaccine, even among the medical and para-medical personnel. The state government is giving the vaccine to pregnant women and high-risk groups, those who have diabetes, hypertension and obesity. These are co-morbidities that can lead to severity of disease. Influenza is a self-resolving disease and anybody who has these co-morbid conditions should take the vaccine. One needs to take the vaccine every year. This virus outsmarts us. It keeps changing and shifting. Hence, the vaccine composition also has to change year to year. Some years it may not change. While the vaccine is free in a government set up, it costs Rs 800 in a private sector.

MANOJ MORE: How efficient is this vaccine and can one be secure for at least a year?

DR CHADHA: Vaccine efficacy is between 60 and 70 per cent, which means that there is 60 per cent chance that you won’t get the disease or get it in a milder form. Immunity lasts for six to eight months. The vaccine should be taken between April and May, so that monsoon and winter months are covered. For Pune and Maharashtra, this is the appropriate time to get vaccininated.

SUSHANT KULKARNI: What is the concept of herd immunity? How is it built in a group of people?

DR MOURYA: When the virus gets into your body it starts generating antibodies. According to the public health perspective, herd immunity is when people, by way of natural exposure or vaccination, develop antibodies. It means that at least 70-80 per cent of the population are immune to this virus. In that case, human-to-human transition can be cut.

MANOJ MORE: When should one take Tami Flu (Oseltamavir)?

DR MOURYA: The drug brings down viraemia within 48 hours. But if the symptoms have already progressed and the anti-virals are given on the third or fourth day, it is of little use. However, another point is that everyone who is coming down with these symptoms should not be subjected to laboratory tests. When a person, with sudden onset of fever, runny nose, bad cough or sore throat goes to the doctor, then it is called an influenza-like illness. By physical examination, the doctor can suspect influenza and for people with co-morbidities, the anti-viral is administered. The earlier one starts taking the tablet the more effective is it. However, indiscriminate use of the tablet is bad. You cannot take it just because of a small cough and cold — this could develop resistance against the anti-viral drug.

ALIFIYA KHAN: Due to the change in the clade, has the severity of the virus increased?

DR MOURYA: This season, we have seen more cases of influenza. However, severity of the virus also depends on the immune response among people. Everyone getting influenza does not become critical. Everyone is not coming down with the disease and the message is that there is no need to panic.

SUSHANT KULKARNI: Is climate change emerging as a threat in spreading these diseases?

DR MOURYA: It is a fact that, recently, we have had a prolonged season of dengue and chikungunya due to intermittent rains. Humidity was high and the temperature was conducive for survival of the aedes aegypti mosquitoes. Due to various factors, there are more breeding sites, which led to a rise in vector-borne diseases. Influenza, too, has a distinct seasonality and there is hard data to show it is associated with precipitation and humidity.

ANJALI MARAR: Is there also an increasing threat of diseases from other animals?

DR MOURYA: Yes, at least 60-70 per cent of the diseases are due to zoonotic infections. These are infectious diseases spread between humans and animals. The entire world is concerned about these emerging diseases.

SUSHANT KULKARNI: There is little awareness about various diseases among the economically weakers sections. Most of the time, they are ignored by the public health systems.

DR YADAV: True, there is an entire strata of the society who do not avail healthcare from a proper medical facility but go to quacks. Virologists have field experience. We have seen that people would not directly approach us but would only rather come via quacks, especially in rural areas. They, perhaps, can be used as tools to create awareness about health education. Community involvement in public health is crucial.

AMITABH SINHA: As a public health professional, what do you think are the three-four big challenges in terms of creation of infrastructure, research and education, and industry collaborations?

DR MOURYA: The number of medico and para-medicos per lakh population is very less in the country. Like other developing countries, we, too, have our share of diseases — some can be prevented by vaccines, while others need a cost effective diagnosis. The industry should give more stress on cheaper diagnostics. We do have five star-like hospitals, but lag behind in public health. There is a well-defined public infrastructure, but we also need doctors from cities to come back to villages.

(TRANSCRIBED BY ANURADHA MASCARENHAS)