New York, Jun 10 (IANS): Scientists still predict a safe and effective vaccine against SARS-CoV-2, the virus that causes COVID-19 could take at least 12-18 months to develop, according to a new report from the New York Times.

In a virtual roundtable, Siddhartha Mukherjee, an Associate Professor of medicine at the Columbia University talked about how quickly the effective vaccine can be developed.

According to the experts, the hopes are that it will be within a year, but that is not in any way guaranteed.

"That projection will be refined as time goes on -- and a year assumes that everything goes smoothly from this point forward. That's never been done before. And safety cannot be compromised," said Dan Barouch from the Centre for Virology and Vaccine Research at Beth Israel Deaconess Medical Centre.

During the discussion, George Yancopoulos, founder, president and chief scientific officer of Regeneron, said that most people don't realise that successfully inventing and developing any new drug or vaccine is quantifiably among the hardest things that human beings try to do.

The goal of a vaccine is to raise an immune response against a virus or a bacterium, the scientists said in the New York Times.

Later, when a vaccinated person is exposed to the actual virus or bacterium, the immune system will then block or rapidly control the pathogen so that the person doesn't get sick, according to Barouch.

He added that vaccine development for a new pathogen traditionally takes many years or even decades.

The process includes small-scale manufacturing, phase 1, phase 2 and phase 3 clinical trials, and then regulatory approval and large-scale manufacturing.

For SARS-CoV-2, the goal is to compress these timelines considerably without compromising safety, which is absolutely critical for any vaccine that will be given to large number of individuals.

Earlier this month, Claudio Colosio Unimi Professor, Department of Health Sciences University of Milan (Italy) had told IANS that 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.

Colosio has been extensively handling the Covid-19 pandemic. When queried about a vaccine still not appearing on the horizon, he said there is no vaccine for HIV infection yet (and people still survive).

However, last month Global pharmaceutical major Pfizer said that it believes that a vaccine to prevent Covid-19 could be ready by the end of October.

The company's CEO Albert Bourla had said that its company -- Pfizer -- is conducting clinical trials in the US and Europe for the BNT162 vaccine programme to prevent Covid-19 in collaboration with German mRNA company BioNTech.