By Sumit Saxena New Delhi, July 28 : After Delhi seemed to be overwhelmed by the Covid-19 catastrophe, a respite may be in sight with the number of cases beginning to decline consistently, and it appears that the curve may plateau soon. Could this become a ground for reopening schools and colleges in New Delhi so that students can achieve herd immunity against the coronavirus? Would it really work? A specialist of infectious diseases Issac Bogoch, at University of Toronto, Canada, thinks otherwise. Bogoch insists that Covid-19 is an extremely contagious infection, and it can be devastating for people over 60 years of age. What is exactly herd immunity? It is a kind of indirect protection from infectious diseases. 'Herd immunity' ensures that a large percentage of the population becomes immune to infections like Covid-19, and it can be achieved either through exposure to the infection or via vaccination. India on Tuesday registered 47,703 fresh Covid-19 cases taking its tally to over 14.83 lakh cases while with 654 new deaths, fatalities crossed 33,425. The recovery rate has improved to 63.92 per cent. "We have to be very careful with the concept of allowing people to get infected with this virus to develop natural (herd) immunity," said Bogoch in an interview with IANS. Below are excerpts from an exclusive chat: Q: Recently, few experts recommended that schools may be reopened in New Delhi, as this may help in developing herd immunity. Do you think this concept of herd immunity is really going to work in bringing things back to normal? Would children not act as carriers of the virus infecting the adults in their family and neighbourhood? A: We have to be very careful with the concept of allowing people to get infected with this virus to develop natural (herd) immunity. This approach does not seem to work (in this case). This is a very contagious infection, and it is clear that the virus can be devastating to those over the age of 60 or with underlying medical conditions. Also, in many areas that had widespread epidemic, once they have their epidemic under control, these areas are still far from what it may take to reach some degree of herd immunity. Q: In India, a trend has been noticed that patients who have recovered from the viral infection have had their lungs in bad shape. Also, Covid-19 is considered responsible for strokes and neurological disorders; Could we say Covid-19 is no longer a respiratory disease? A: Many respiratory infectious diseases, including COVID-19, have manifestations outside of the lungs. We are seeing examples of clinical issues outside of the lungs in those with COVID-19, such as blood clots, and smell and taste disturbances. Q: Is it possible to eliminate Covid-19 anytime soon? How long do you think people would have to wear masks and adhere to social distancing norms, is the virus going to stay with us for a long time? A: Unfortunately, in much of the world I do not think it is possible to eliminate COVID-19 in the pre-vaccine era. That doesn't mean we should not strive toward elimination -- we should do everything possible to keep community transmission as low as possible, but for most places, elimination is an unrealistic goal. Even if the infection is eliminated in some small region, it can be easily re-imported once travel resumes. A vaccine, even an imperfect vaccine, will significantly help with elimination strategies. Q: Do you think the Oxford Covid-19 vaccine has the potential to be a real game-changer, not only for a Covid-19 vaccine but for the development of future vaccines? A: The results of the Oxford COVID-19 vaccine from Phase 1 and Phase 2 clinical trials looks very promising, but we still need to be patient and wait for Phase 3 clinical trial results, which will inform us on if this vaccine reduces the chances of acquiring COVID-19. This vaccine and others in development stages look extremely promising, but I do not want to get overly excited just yet -- let's see how these vaccines perform in larger clinical trials first. Q: A potential coronavirus vaccine developed by Oxford University in association with pharmaceutical giant AstraZeneca has produced a promising immune response in a large, early-stage human trial. Do you think this is the step towards developing a vaccine providing long-lasting protection against Covid-19? A: This is a major step forward. We still need to see the results of larger human trials, and these are ongoing for this vaccine and a few other COVID-19 vaccines too. An effective vaccine will be an essential step toward returning to life as we remember before COVID-19. (Sumit Saxena can be contacted at sumit.s@ians.in) /IANS