‘Study on covid vaccines’ efficacy soon’

New Delhi: The National Institute of Virology (NIV Pune) plans to conduct a study to determine the efficacy of vaccines with covid variants.

The study will find out why people have been contracting covid even after taking booster shots , said Pragya Yadav, the NIV scientist who isolated the first SARS-CoV2 virus in 2020.

Asked if there’s a need for a 4th dose, Yadav said in an interview, “Before we talk about 4th dose, we should enhance coverage of 3rd precautionary dose to enhance the immune response.”

Only about 228.7 million Indians have received the third dose—the booster shot—so far.

Discussing the present testing strategy, Yadav said the government should increase the number of samples taken for genome surveillance. At the moment, only 5% of samples are taken for genome surveillance which she said is inadequate to determine the genome in circulation. Edited excerpts:

How do you see the present covid surge in the country?

There was a lot of concern when last year Omicron emerged, and everybody was in a panic. Gradually, many Omicron variants appeared which other countries reported too. Fortunately, India did not suffer any major surge. Currently, we have more than 37,000 active cases. It is time for everyone to be on alert and take precautions. When XBB variant, a recombinant variant of Omicron emerged with two of the variants—BA.2.75 and BA.2.10.1—there was a concern that cases would go up. However, cases did not go up with emerging XBB.1.15 variant like other countries. In India, currently XBB.1.16 is in circulation with almost 75% prevalence in total cases. Surely, it will not be as bad as we saw in Delta because Omicron is mild and most cases are asymptomatic. But from a public health perspective, yes there is alarm, and we follow safe practices including the use of masks, hand hygiene and physical distancing as much as possible.

What is the situation in other countries?

XBB.1.16 is now spreading gradually in about 28 countries. According to the data that is currently accessible, although there has been increase in cases from 5% to 7% in the US, the virus XBB.1.15 still dominates most of the country. Whereas it has been shown in the past that dominant variants replicate more quickly, XBB.1.16 has the benefit of 1.5-fold transmission over other variants due to its higher R0 number.

India has hybrid immunity due to natural infections and excellent vaccine programmes. However, many studies have proven that vaccines cannot prevent infection but reduce the severity and hospitalization and mortality due to covid-19. Viruses have the propensity to mutate, and some of these alterations may be more likely to evade the immune response generated by vaccination or natural infections but immunization would still protect from deaths and severity.

Is NIV doing any study to understand the immune escape response of the vaccine?

The vaccine neutralizing study is now being planned in order to comprehend the vaccine response.

Deaths are being reported. Are they a cause of worry?

It’s time to monitor these cases and analyse the data properly. The majority of these fatalities affect the elderly and those who are either unvaccinated or have concomitant illnesses along with covid-19.

Do we need a 4th vaccine dose?

Before we talk about 4th dose, we should enhance coverage of 3rd precautionary dose to enhance the immune response. The vaccines in India currently in use are mostly based on the SARS-CoV-2 variant from the Wuhan strain. Though, the Omicron have undergone significant mutations but many studies have proven that hybrid/ booster immunity still protects with severity and deaths. Booster vaccination provides long-term cellular immunity.

Along with covid surge, influenza (H3N2) is also on the rise? Do you think that there is a threat of co-infection?

In order to strengthen the detection of covid-19 , surveillance was initiated amongst SARI/ILI. Nevertheless, the incidence of such co-infection is not particularly high and till date only few cases of covid-19 and H3N2 coinfection had been reported.

The coverage of booster dose is low. Why is there hesitancy for booster dose?

The booster dose vaccine hesitancy could be due to many reasons including misinformation circulating and non-mandate of booster dose.

Do we need a 4th vaccine dose?

Before we talk about 4th dose, we should enhance coverage of 3rd precautionary dose to enhance the immune response. The vaccines in India currently in use are mostly based on the SARS-CoV-2 variant from the Wuhan strain. Though, the Omicron have undergone significant mutations but many studies have proven that hybrid/ booster immunity still protects with severity and deaths. Booster vaccination provides long-term cellular immunity.

Along with covid surge, influenza (H3N2) is also on the rise? Do you think that there is a threat of co-infection?

In order to strengthen the detection of covid-19 , surveillance was initiated amongst SARI/ILI. Nevertheless, the incidence of such co-infection is not particularly high and till date only few cases of covid-19 and H3N2 coinfection had been reported.

The coverage of booster dose is low. Why is there hesitancy for booster dose?

The booster dose vaccine hesitancy could be due to many reasons including misinformation circulating and non-mandate of booster dose.

What kind of testing strategy should be done right now?

Testing is currently being done on patients who are visiting hospitals with symptoms. However, to improve the testing, perhaps random sampling at various locations may be conducted at different entry ports. Currently, the fewer samples are being tested including the sequencing of only 5% of these samples, this percentage can be raised, which will aid in the production of additional genomic data.

Testing is currently being done on patients who are visiting hospitals with symptoms. However, to improve the testing, perhaps random sampling at various locations may be conducted at different entry ports. Currently, the fewer samples are being tested including the sequencing of only 5% of these samples, this percentage can be raised, which will aid in the production of additional genomic data.