The analysis was conducted after 20 participants developed the virus and examined how many had received the vaccine versus a placebo.
Moderna's data provide further validation of the promising but previously unproven mRNA platform, which turns the human body into a vaccine factory by coaxing cells to make virus proteins that the immune system sees as a threat and attacks. Moderna expects it to be stable at normal fridge temperatures of 2 to 8 degrees Celsius (36 to 48°F) for 30 days and it can be stored for up to 6 months at -20C.
Moderna expects to have enough safety data required for USA authorisation in the next week or so and the company expects to file for emergency use authorisation in the coming weeks.
Pfizer's vaccine must be shipped and stored at -70degC, the sort of temperature typical of an Antarctic winter.
To confirm the effectiveness rate of its vaccine, Pfizer said it would continue its trial until there were 164 COVID-19 cases.
The US government, faced with the world's highest known number of Covid-19 cases, could have access next year to more than 1 billion doses from Moderna and Pfizer, more than needed for the country's 330 million residents.
As part of Operation Warp Speed, the federal government in the USA signed an agreement with Pfizer in July for up to 600 million doses of the Covid-19 vaccine.
The United States has the world's highest known number of COVID-19 cases and deaths with more than 11 million infections and almost 250,000 deaths.
Pfizer is planning to ask the US Food and Drug Administration (FDA) for emergency use authorisation of its Covid-19 vaccine candidate very soon.
The 95 cases of Covid-19 included several key groups who are at increased risk for severe disease, including 15 cases in adults aged 65 and older and 20 in participants from racially diverse groups.
The trials were created to measure whether the vaccines stop people from getting sick rather than whether they prevent transmission, which remains to be tested.
Most side effects were mild to moderate. Most of these complaints were generally short-lived, Moderna said.
Numerous countries have signed deals with the company already to receive millions of doses of its candidate vaccine. The US government also has an option for another 400 million doses.
The company hopes to produce between 500 million and 1 billion doses in 2021, split between its U.S. and global manufacturing sites, depending in part on demand.
Moderna also said it would use its data to seek authorization in Europe and other regions. The Commission has secured to date at least 1.2 billion doses and fulfils its commitment to ensuring equitable access to safe, effective and affordable vaccines not only for European Union citizens but also for the world's poorest and most vulnerable people. Russian Federation licensed its Sputnik-V COVID-19 vaccine for domestic use in August before it released data from large-scale trials.
According to the interim trial results, Russia's Sputnik V vaccine is 92% effective at protecting people from COVID-19.