“Since the development and availability of Covid-19 vaccines is subject to a great deal of uncertainty, the government is pursuing various options,” the Federal Office of Public Health said in a statement.

Switzerland has now secured, in total, around 7.5 million doses of US biotechnology firm Moderna's vaccine.

It has also signed contracts for around 5.3 million doses of the AstraZeneca vaccine and, in a deal announced Monday, around three million doses of the Pfizer-BioNTech vaccine.

READ: Why the Swiss are banking on a more cautious approach to Covid-19 vaccine 

The wealthy Alpine nation, population 8.6 million, has therefore secured around 15.8 million vaccine doses.

With all three manufacturers' vaccines, two doses are required per person.

The three different vaccines are currently awaiting approval from the Swissmedic national regulator. “The federal government is still in discussion with various vaccine manufacturers,” the statement said.

“Since it is not yet clear which vaccines will prevail, it is targeting a number of… vaccines based on different technologies.”

READ: Will residents in Switzerland be allowed to go to Germany for Covid-19 vaccination? 

Like the vaccine produced by Pfizer and BioNTech, US firm Moderna's vaccine is based on a new technology that uses genetic material in the form of mRNA (messenger ribonucleic acid).

On Tuesday, Britain became the first Western country to start a mass coronavirus vaccine campaign with a 90-year-old pensioner receiving her initial dose of the Pfizer-BioNTech jab.

Switzerland will not be among the first countries to do likewise, as it does not have a process for emergency authorisations of vaccines or drugs.

The authorities have said once a vaccine is approved, they hope to scale up quickly to provide free jabs for all by mid-2021.

Switzerland has recorded 357,121 positive tests and 5,099 deaths from the coronavirus.