By Sumit Saxena New Delhi, June 4 : It is not possible to develop a vaccine for Covid-19 soon, as the RNA virus changes very quickly and this makes it difficult to create a good vaccine, says Claudio Colosio Unimi Professor, Department of Health Sciences University of Milan, Italy. Claudio as the Director, Occupational Health Unit of the Hospitals Saints Paolo and Carlo of Milano, has been extensively handling the Covid-19 pandemic. When queried about a vaccine still not appearing on the horizon, Claudio said there is no vaccine for HIV infection yet (and people still survive). And is there a possibility to develop a vaccine for Covid-19, and how soon is it possible? Claudio replied "Not very soon. RNA viruses change very quickly and this makes it difficult to create a good vaccine." Elaborating on the Italian experience of Covid-19, -- a possibility the population has developed herd immunity after experiencing the viral infection attack for close to 6 months -- Claudio said "No. Today the rate of immunization is in the order, depending on the areas, of 2-15 per cent. Very far from herd immunity." Italy was worst hit by coronavirus, currently the number of cases have reduced drastically from 5,000 to less than 300 cases a day. Comparatively, India is just where Italy was months back. More than 9,000 cases were reported on Thursday. It also posted over 5,000 for over two weeks, before crossing 6,000, then 7,000 and 8,000 in rapid succession. On suggestions for India from his experience in Italy, Claudio said: "Doing the big sacrifice of locking down if possible. "Otherwise mandatory mask: surgical mask is ok for most situations. However, I understand how difficult this is in India. "Finally, social distancing. Otherwise it would be very difficult to stop the chain of infection. You should be satisfied when the number of subjects infected by a single coronavirus subject will be under 1." Citing the Covid-19 study at the University of Milan, Claudio said: "We are studying the trends of infection among healthcare workers and whether the approaches are adequate to avoid the spreading of the disease ("contact tracing")." Queried on the increasing levels of pollution, especially in Indian context which has many polluted cities, aiding the spread of coronavirus, Claudio said "There is not any evidence of this. Just only a hypothesis. I don't trust it." When asked, if the current trend of number cases would lead India in the US, UK direction, where the viral infection ran havoc claiming thousands of lives, Claudio said "This is something we cannot anticipate from here. For sure the risk is highest in the most populated regions, and in any place where social distancing is difficult. And India suffers both these risk determinants!" Responding to a query on Italy's efforts in bringing down deaths due to Covid-19, (according to WHO since May 25 Italy has reported less than 100 deaths a day), Claudio said "With social distancing and removing these people (vulnerable group) from the more risky jobs, for example some departments in the hospitals for health care workers. "A good solution requires smart job done." (Sumit Saxena can be contacted at sumit.s@ians.in) /IANS