Pfizer chief executive Albert Bourla said Tuesday he understood concerns around the speed at which pharmaceutical companies have produced Covid-19 vaccines, but insisted that no corners had been cut.

As Britain on Tuesday became the first Western country to start a mass coronavirus vaccine campaign, using the new Pfizer-BioNTech jab, Bourla said people should feel confident that it is safe and effective.

"We didn't cut any corners," he told a virtual media briefing hosted by the International Federation of Pharmaceutical Manufacturers and Associations (IFPMA).

The vaccine, based on new technology, has been tested "in the exact same way as we are testing any vaccine that is circulating out there," Bourla assured.

In fact, he added, "this vaccine actually was tested, because of the scrutiny, with even higher standards in terms of how we do things."

The Pfizer-BioNTech jab is one of several vaccine candidates approaching approval in a number of countries, bringing hope for an end to the pandemic that has killed more than 1.5 million people worldwide and ravaged economies.  

Bourla said  he understood the concerns around the speed at which the vaccines had been developed. 

"Always there are people who are sceptical about vaccines, but I have to say they are wrong," he said.

"I can imagine that in this case, because the products, the vaccines or the medicines are developed very fast that it is even worse because it has been severely politicised, particularly in the US.

"That makes people confused. They don't know who to believe and what to believe, because the discussion was happening on political rather than on scientific terms."

But he stressed that the companies were intent on ensuring that only safe and effective vaccines make it to market, and "the regulators are very careful."

For those wary of getting a jab, Bourla said: "I understand their concerns, but they need to think twice.

"The decision to vaccinate, or not, is not affecting only your health. It is affecting the health of others, and likely the health of people you love," he said.

"If you don't vaccinate you are becoming the weak link that will allow the virus to replicate."