Could bird u turn into the next pandemic?
essential to maximise benets, minimise risks, and increase alternative options. However, at any given point of time, a decision must ultimately be made within available options, given available knowledge. In my own family, fully aware of the TTS reports from Europe and UK, I chose to go ahead with Covishield for high-risk older adults, as soon as possible. My low-risk daughters received Covaxin. Sensibly, Covishield was not used to vaccinate children. The risk-benet analysis was unfavourable, with risk of severe infection and death in children being ten to hundred-fold lower than in adults. There were some missteps also. First and foremost, we have a data problem. Despite having given nearly a billion doses of Covishield, almost all our knowledge of critical side eects like TTS comes from outside India. The new digital India can do better. Second, while it is acceptable to choose an imperfect best option, we need to be nimbler in creating alternatives. For example, protein-subunit vaccines like Covovax (also made by Serum Institute) could have replaced Covishield for boosters. I do note that the risk of TTS was much lower in subsequent doses and the older population that received boosters was at the least risk.
A question that comes up repeatedly is whether there has been a recent increase in thrombotic events like heart attacks and strokes in otherwise healthy young people. Indian data is unfortunately lacking, but western data conrms a large increase in young heart attacks and strokes after COVID-19. As mentioned previously, this risk was highest in the unvaccinated and increased after every surge in infections. SARS-CoV2 never quite left. It keeps circulating and evolving to escape immunity, periodically giving rise to infection surges that are mostly ignored due to milder symptoms in a partially immune population. For example, based on viral load in sewage and sequencing of wastewater, we had a silent surge of undiagnosed JN.1 SARS-CoV2 infections in January this year. Whether these undetected COVID-19 infections are increasing clotting risks is not established, but it is far more likely than the concerns about a vaccine given more than two years ago doing so. Unfortunately, we have not been able to develop an adequate vaccine for preventing infection so far, at least over a long period. I fear that with anti-vaccine disinformation reaching new heights, enthusiasm for vaccine research will decline. That would be the real tragedy.
To conclude, vaccines are some of the most eective public health interventions against infectious diseases. We need to stop the fear-mongering and celebrate the great Indian COVID-19 vaccination drive that saved innumerable lives. If at all I had a wish, it would be that more of us received them sooner.
(Dr. Anurag Agrawal is Dean, BioSciences and Health Research, Trivedi School of Biosciences at Ashoka University.
anurag.agrawal@ashoka.edu.in)
Several states across the country including Kerala, Maharashtra, Chhattisgarh, and Jharkhand among others have been directed to stay vigilant after the emergence of a highly pathogenic avian inuenza that has spread to cattle was detected in eight U.S. states. While the Centre has asked for vigilance, the World Health Organization (WHO) expressed deep concern regarding the increasing transmission of H5N1 bird u to other species, including humans. ”The current bird u outbreak, which originated in 2020, has aected not only ducks and chickens but also cows and goats, which is why the u has been described as “a global zoonotic animal pandemic,” it said.
WHO is warning about the risk of the virus evolving to infect humans and gaining the ability to transmit from human-to-human. Although there is no evidence of human-to-human spread yet, the mortality rate among those infected through contact with animals remains high. Over the past 15 months, WHO has documented 889 human cases across 23 countries, resulting in 463 deaths, a mortality rate of 52%
The Central government in India maintains that Highly Pathogenic Avian Inuenza (HPAI), commonly known as bird u, was rst detected in the state of Maharashtra in February 2006. Since then, the country has experienced annual outbreaks of HPAI in dierent regions, leading to substantial economic losses.
WHO is warning about the potential risk of the virus evolving to infect humans and gaining the ability to transmit from human-to-human
The disease has been reported in 24 states, resulting in the culling of over 9 million birds to control its spread. It’s important to note that vaccination against HPAI is not permitted in India. The Centre has maintained that with the long-term use of vaccination either the disease has become endemic and therefore widespread, or the infection in aected animals is too dicult to detect. Accordingly, the Government of India does not permit use of any vaccine against avian inuenza in the country.
An article titled, ‘Bird u in US cows where will it end’ in Nature on May 8, 2024, notes that various forms of the
H5N1 virus have been circulating since the 1990s. A particularly deadly variant that was rst detected in 1996 killed millions of birds and has been found in numerous mammalian species, including seals and mink. But until now, cows were not among the virus’s known hosts. US ocials rst announced on 25 March that H5N1 had been found in cattle. Cows from 36 herds in 9 states have tested positive as of 7 May. Tests of pasteurized milk have found no living virus. But the virus’s increasing ubiquity has made scientists uneasy. It adds further that from a human perspective, cows might be one of the worst possible animal reservoirs for inuenza because of their sheer number and the degree to which humans interact with them. Culling poultry has curbed previous bird u outbreaks, that isn’t a viable option for cattle. The animals are too valuable and, unlike birds, don’t seem to die from the infection.
(bindu.p@thehindu.co.in)
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