Novavax Vaccine: How Effective Is It? When Will It Be Approved?

What exactly did the studies say? Why is this important for India? FIT breaks it down.

(Photo Courtesy: iStock)

The COVID-19 vaccine developed by US firm Novavax has demonstrated overall efficacy of 89.3 percent in a phase 3 clinical trial in the United Kingdom, revealed interim data shared by the company.

The vaccine was also found to be highly effective against the possibly more contagious variant that was identified there earlier. However, it offered significantly lesser protection against the one that was originally identified in South Africa, AFP reported.

“With today’s results from our UK Phase 3 and South Africa Phase 2b clinical trials, we have now reported data on our COVID-19 vaccine from Phase 1, 2 and 3 trials involving over 20,000 participants.”

Stanley C Erck, President and Chief Executive Officer, Novavax

He added, “NVX-CoV2373 is the first vaccine to demonstrate not only high clinical efficacy against COVID-19 but also significant clinical efficacy against both the rapidly emerging UK and South Africa variants.”

What exactly did the studies say? Why is this important for India? FIT breaks it down.

What did the UK study find?

The study enrolled more than 15,000 participants between 18-84 years of age, including 27 percent over the age of 65, the company shared on 28 January.

The first interim analysis is based on 62 cases, of which 56 cases of COVID-19 were observed in the placebo group versus six cases observed in the vaccine group, resulting in a point estimate of vaccine efficacy of 89.30 percent.

Of the 62 cases, 61 were mild or moderate, and one was severe (in placebo group).

Based on PCR performed on strains from 56 of the 62 cases, efficacy by strain was calculated to be 95.6 percent against the original COVID-19 strain and 85.6 percent against the UK variant strain.

The interim analysis included a preliminary review of the safety database, which showed that severe, serious, and medically attended adverse events occurred at low levels and were balanced between vaccine and placebo groups.

The vaccine is also being tested in a trial in the US and Mexico, which has recruited 16,000 of 30,000 participants.

How effective was the vaccine in South Africa?

In the South Africa Phase 2b clinical trial, 60 percent efficacy for the prevention of mild, moderate and severe COVID-19 disease was observed in the 94 percent of the study population that was HIV-negative.

This study enrolled over 4,400 patients beginning in August 2020. Preliminary sequencing data is available for 27 of 44 COVID-19 events; of these, 92.6 percent (25 out of 27 cases) were of the South African variant.

Part of the findings suggested that prior infection with COVID-19 may not completely protect against subsequent infection by the South Africa escape variant, however, vaccination with Novavax provided ‘significant protection’, said the company.

“The 60 percent reduced risk against COVID-19 illness in vaccinated individuals in South Africans underscores the value of this vaccine to prevent illness from the highly worrisome variant currently circulating in South Africa, and which is spreading globally,” it added.

When is it expected to apply for authorisation?

Novavax expects to share further details of the UK trial results as additional data become available. Additional analysis on both trials is ongoing and will be shared via prepublication servers as well as submitted to a peer-reviewed journal for publication. The company initiated a rolling submission to the United Kingdom’s regulatory agency, the MHRA, in mid-January.

The company has said that they expect it will be two to three months before they are ready to apply for authorization with regulators, reported Reuters.

British Prime Minister Boris Johnson tweeted that the results were “good news.” “Our medicines regulator will now assess the vaccine, which will be made in Teesside. If approved, we have 60m doses on order,” he added.

The company is already stockpiling vaccine at six operating manufacturing locations, and said it expects a total of eight plants in seven countries to produce at the rate of 2 billion doses per year, including from the Serum Institute of India.

Novavax is also one of the six candidates that were backed by the US government’s Operation Warm Speed, through which it received $1.75 billion.

Is 60 percent efficacy good enough?

Dr Amesh Adalja, an infectious disease expert at the Johns Hopkins Center for Health Security, said the results were indeed positive.

“We’ve gotten spoiled because we’ve seen the Moderna and Pfizer numbers. I know people are going to be alarmed, but 60 percent efficacy against the new variant is acceptable,” he told Reuters, noting that the FDA initially said it would approve a vaccine that was at least 50 percent effective.

Professor Shabir Maddi, Executive Director of the Vaccines and Infectious Diseases Analytics Research Unit (VIDA) at Wits, and principal investigator in the Novavax COVID-19 vaccine trial in South Africa, said in the company press release, “The 60 percent reduced risk against COVID-19 illness in vaccinated individuals in South Africans underscores the value of this vaccine to prevent illness from the highly worrisome variant currently circulating in South Africa, and which is spreading globally.”

“I am encouraged to see that Novavax plans to immediately begin clinical development on a vaccine specifically targeted to the variant, which together with the current vaccine is likely to form the cornerstone of the fight against COVID-19,” he added.

What does this mean for India?

The SII has applied to Indian regulators to conduct a small trial of the vaccine in India, and expects to hear back soon, Chief Executive Adar Poonawalla told Reuters on Friday after the UK trial data had been shared. The vaccine is expected to be launched in India in June, he added.

“We have already applied to the drug controller’s office for the bridging trial, a few days ago,” Poonawalla said.

He had also told the news agency earlier this month that his company would manufacture “upwards of 40-50 million doses per month” of the Novavax vaccine from around April.

What type of vaccine is this the Novavax candidate?

NVX-CoV2373 is a protein-based vaccine candidate engineered from the genetic sequence of SARS-CoV-2, the virus that causes COVID-19 disease.

It can neither cause COVID-19 nor can it replicate, is stable at 2°C to 8°C (refrigerated) and is shipped in a ready-to-use liquid formulation that permits distribution using existing vaccine supply chain channels.

(This was first published on FIT and has been republished with permission.)