The Novavax vaccine is 89% effective against Covid-19 in a UK study

However, the vaccine was less effective in a separate mid-stage study in South Africa, where yet another variant has been extended. In South Africa, Novavax’s firing was approximately 49.4% effective against Covid-19 in the study. Preliminary results showed that more than 90% of the sick subjects for whom sequencing data were available were infected with the new variant circulating in South Africa.

In light of the lower efficacy in South Africa, Novavax said it has begun work on a modified version of its vaccine that is better targeted to the strain that was first identified and plans to begin tests in the second trimester.

Overall, however, the positive performance points to another vaccine that will soon join the arsenal of shots available in some countries, as health authorities face limited supplies as they compete to inoculate residents.

“We now have a vaccine, the first vaccine to be effective not only in the original Covid-19 soa prototype, but in two varieties of strains, one in the UK, one in South Africa,” the director said in an interview Novavax executive Stanley Erck. “It’s the only data that shows we can get effectiveness against all three.”

In the UK study, Novavax said that according to tests in 56 of the 62 cases of Covid-19, the vaccine appeared to be 95.6% effective against the original strain of Covid-19 and 85.6 % against the UK strain.

Novavax, which has never introduced a vaccine to the market, published the results of its studies in a press release. The data have not been subjected to the standard review by external experts preceding publication in a medical journal.

The Gaithersburg, Maryland-based company said it has begun the process of requesting that British health regulators make clear use of the company’s vaccine in the country.

Novavax said it would provide the new data to U.S. regulators, which could lead to an authorization in April. But U.S. regulators may not decide on the vaccine until they see the results of an ongoing third-phase study testing the shot in the United States and Mexico.

The study has enrolled 16,000 people, with a target of 30,000, and Novavax said it is possible that the first results will come by the end of March.

Pfizer vaccines Inc.

and its partner BioNTech SE,

as well as Modern Inc.,

have been authorized for use in the US, while a shot from AstraZeneca PLC and Oxford University is obtained in the UK

Novavax has one of the most advanced vaccines in development. Johnson & Johnson does the same,

which hopes to publish the results of its final phase or phase 3 vaccine test before next week.

The impetus for vaccination has gained new urgency since the emergence of strains in the UK and South Africa, as well as in Brazil, which threatens to spread faster than the old version of the virus and evade some treatments.

Researchers have also been trying to see to what extent vaccines will be protected against new variants and whether Covid-19 drugs will continue to work.

Moderna Inc. said this week that it would develop a booster shot after lab tests showed the Covid-19 vaccine had fewer neutralizing effects against the variant circulating in South Africa.

Moderna and Pfizer have said laboratory tests suggest their vaccines would still be effective against variants identified in the UK and South Africa. Both variants have been detected in the US, as has the one identified in Brazil.

The Novavax vaccine contains proteins that resemble the “peak” proteins found on the surface of the coronavirus.

The researchers designed the spike-like proteins that are initiated by firing to trigger an immune response that can later be defended against the actual coronavirus if a vaccinated person is exposed to it.

Novavax manufactures proteins from insect cells. The vaccine also contains an adjuvant, designed to enhance the immune responses generated by the vaccine, derived from the bark of an evergreen tree native to Chile.

The protein-adjuvant combination is generally similar to the design of some vaccines against other diseases, such as the latest shingles from GlaxoSmithKline PLC.

Novavax began the UK’s Phase 3 central study in September and enrolled some 15,000 people.

The trial tracked whether adults who received two doses of the vaccine, three weeks apart, experienced mild to severe Covid-19 at a slower rate than study subjects who obtained a placebo, at starting one week after the second dose.

The Pfizer-BioNTech and Moderna vaccines were more than 94% effective in phase 3 trials, while the AstraZeneca vaccine was 62% effective in many study subjects.

Novavax said there were “low levels” of serious side effects that were balanced between those who received the vaccine and those who received a placebo in the UK study.

In the smallest South African phase 2 study, Novavax compared his vaccine with a placebo in about 4,400 people. This study also included a subgroup of HIV-positive people.

Excluding the results of HIV-positive people, the vaccine was about 60 percent effective, Novavax said.

Health experts believe that a flu vaccine works well if it is 60% effective, although other vaccines can exceed 90%. The U.S. Food and Drug Administration has said Covid-19 vaccines should be at least 50% effective.

The study of the Novavax phase 3 vaccine in the US and Mexico began in late December. The start of the trial was delayed because Novavax was experiencing some manufacturing issues.

It was the first protein-based Covid-19 vaccine to enter large-scale testing in the United States.

The federal government agreed last July to provide $ 1.6 billion to Novavax to help fund testing and manufacturing of preparations for its vaccine and to acquire 100 million doses.

In August, the UK government agreed to buy 60 million doses of the Novavax vaccine and collaborate with the company in the phase 3 study.

Last year, Novavax said that in a small initial study of healthy volunteers, their vaccine generated promising immune responses and was generally well tolerated.

If allowed to be used, the vaccine could generate sales of $ 3.455 billion this year, according to the average estimate by analysts surveyed by FactSet.

—Gregory Zuckerman contributed to this article.

Write to Peter Loftus to [email protected]