Vaccination must to avert future infection: experts

Health officials taking part in the dry run of the inoculation programme in Hyderabad on Friday.

Health officials taking part in the dry run of the inoculation programme in Hyderabad on Friday.

SARS-COV-2 virus is here to stay, hence those refusing to be vaccinated or not having access to an effective vaccine, will remain susceptible to infection. The infection will persist in the human population at a lower intensity called the endemic phase. However, future virus waves can be averted if vaccination of the population is initiated soon, say public health experts.

“We still see around 20,000 new cases every day at the national level and over 300 in Telangana. Subsequent waves will depend on proportion of the population with antibodies to COVID and the time it takes for antibodies to disappear and the population becoming vulnerable again,” asserts Public Health Foundation of India’s Indian Institute of Public Health-Hyderabad Director Dr. G.V.S. Murthy.

This coupled with factors like crowding, partying in close contact, and amenable weather conditions, among others, can result in the next waves, he says, and points out that a vaccine has become a reality in 10 months as against more than 10 years. It is because of the pandemic that clinical development, safety, dosage, and vaccine efficacy phases got “dovetailed and telescoped” to make it a reality.

The director says there are 30 vaccines in clinical trials and more than 200 in various stages of development with platforms of RNA, DNA, non-replicating viral vectors and inactivated vaccines. RNA and DNA based vaccines have not been developed and licensed for human use in the past and ‘transformational’.

There is no virus particle either live attenuated or killed virus particles in them and can be made rapidly in a lab. Since, they are based on genetic sequence of the virus development process to be fast tracked in the event of a pandemic. They are also able to generate a robust immune response and the vaccine currently being rolled out in United States and United Kingdom is of this type.

However, they have to be kept at extremely low temperatures during storage, transportation and at the point of administration, so there are logistic challenges. Non-replicating viral vector vaccines can also be made fast, are safe and effective immunologically as seen with an Ebola vaccine candidate, explains Dr. Murthy.

Third kind is inactivated virus technology that have been licensed previously but “they do not generate as strong of an immune response unless used alongside, as an example, an aluminium adjuvant. Conventional vaccines like DPT or TT vaccines are of this kind and are easier to administer as they do not require stringent cold chains,” he maintains.

“Overall efficacy of such vaccines may be lower than the other two kinds. But, because it may be possible to administer these vaccines to a larger number of people in a shorter period of time, they also are very useful to increase ‘herd immunity’ substantially to prevent high infection rates due to quick coverage overall,” he says.

The big task with all the vaccines is administering in two doses, one month apart. Priority should be for frontline workers, aged, and those with co-morbidities. It should also be provided free-of-cost to those who cannot afford it. As initial production may not match the needs of the population like ours, it “may be useful to couple vaccine administration with an antibody test preceding the vaccine in the first few months as a short term measure,” suggests the director.

By year-end, the vaccine should be made available at government designated vaccination centres and provided universally. Those who can afford to pay may be directed to the private sector where a wider choice of vaccines at different costs may be available, adds Dr. Murthy.

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Printable version | May 26, 2022 2:37:04 pm | https://www.thehindu.com/news/cities/Hyderabad/vaccination-must-to-avert-future-infection-experts/article33532493.ece