More than 1 billion people could be immunised against coronavirus by the end of next year with shots from the first two companies to reveal positive results, after the latest vaccine was shown to be nearly 95% effective in trials.

With the US’s top infectious diseases official, Anthony Fauci, hailing “the light at the end of the tunnel”, the US biotech firm Moderna announced impressive results for its mRNA vaccine on Monday, a week after interim results for a Pfizer/BioNTech vaccine showed 90% effectiveness.

The inclusion of high-risk and elderly people in the Moderna trial suggested the vaccine would protect those most vulnerable to the disease, said Peter Openshaw, a professor of experimental medicine at Imperial College London, who described the results as “tremendously exciting”.

Though it is more expensive, Moderna’s vaccine could potentially provide a major advantage over Pfizer’s, which requires ultracold freezing between -70C (-94F) and -80C from production facility to patient.

Moderna said it had improved the shelf life and stability, meaning its vaccine can be stored for six months at -20C for shipping and long-term storage, and at standard refrigeration temperatures of 2C to 8C for 30 days.

Moderna said it could potentially manufacture 1bn doses by the end of 2021, adding to a further 1.3bn from Pfizer/BioNTech in the same timeframe. Both vaccines require two doses and are due to be assessed by regulators in coming weeks.

Speaking at a press briefing, Fauci, the director of the US National Institute of Allergy and Infectious Diseases, which co-developed the vaccine, lauded the Moderna jab and others still in trials.

He urged people to continue to observe guidelines to combat the disease. “We should not let the accomplishment of an effective vaccine have us feel we can let our guard down … In fact, it should be an incentive to double down as we then ultimately have the synergy between a vaccine and a public health measure which will get us out of the very difficult situation.”

Stéphane Bancel, the chief executive of Moderna, said: “This has been incredible teamwork. I think none of us probably thought that we could get to this place in the last 10 months.”

Moderna’s interim analysis, based on the first 95 patients with confirmed Covid infections, found the candidate vaccine had an efficacy of 94.5%. The company said it planned to apply to the US regulator, the Food and Drug Administration (FDA), for emergency use authorisation in the coming weeks. In the analysis, 90 of the patients had received the placebo with the remaining five getting the vaccine.

Experts at the World Health Organization (WHO) say the news Monday of another COVID-19 vaccine candidate is encouraging but more information is needed and, as new virus cases surge around the world, it is no time to be complacent.

At their regular COVID-19 news briefing in Geneva, WHO officials reacted to the news from U.S. pharmaceutical company Moderna that its vaccine candidate tested at better than 90% efficacy.