Recent publications from Novavax and Johnson & Johnson on 2019 coronavirus vaccines (COVID-19) show efficacy, but some concerns remain about new variants that have recently become more widespread.
Candidate NVX-CoV2373, a candidate for the 2019 protein-based coronavirus vaccine (COVID-19) from Novavax, reported phase 3 results showing 89.3% efficacy in preventing COVID-19 in participants in the UK.
The results of the study – conducted at a time of significant transmission in the country and an emerging, more transmissible variant that is spreading globally – coincide with the findings of phase 2b which shows a lower prevention of the variant initially observed in South Africa.
The vaccine
NVX-CoV2373 is a vaccine consisting of a full-length, prefusion-tipped protein made from proprietary recombinant nanoparticle technology and a saponin-based Matrix-M adjuvant.
Produced in insect cells, the purified protein is encoded by the genetic sequence of the SARS-CoV-2 spike protein.
With the emergence of new SARS-CoV-2 mutant strains in regions, including south-east England and South Africa, Novavax has begun developing new vaccine strains specified in strain genetic codes, with the expectation that ideal candidates will be provided by booster or in combination as a bivalent vaccine will become apparent in the coming days.
Testing of these newer vaccines would be launched in the second quarter of 2021.
“A major benefit of our adjuvanted platform is that it uses a very small amount of antigen, allowing the rapid creation and large-scale production of combined vaccine candidates that could address multiple circulating strains of COVID-19,” said Gregory M. Glenn, MD, president of research and development Novavax, in a statement.
UK Trial
Investigators enrolled more than 15,000 adult participants between the ages of 18 and 84 years to evaluate the vaccine for a primary endpoint of symptomatic PCR-confirmed COVID-19, beginning at least 7 days after the vaccine dose. recall of participants serologically negative for SARS -CoV-2 at baseline.
More than a quarter (27%) of the study participants were over 65 years of age.
In the first interim analysis of 62 COVID-19 cases, 56 (89.2%) were observed in the placebo arm, compared with only 6 in the vaccine group (95% CI, 75.2 – 95.4). Of the 62 cases, only 1 was severe – from a placebo patient.
The highly transmissible variety of the strain in the UK was detected in more than half of all cases observed, the investigators observed (n = 32). In a post hoc evaluation, investigators reported that NVX-CoV2373 was 95.6% effective against the original COVID-19 strain and 85.6% effective against the UK variant strain.
In an interim analysis of the safety database, investigators observed low, balanced rates of severe and healthcare-associated adverse events in both treatment arms.
Clive Dix, chair of the UK Vaccine Working Group, praised the results as “spectacular” and expressed encouragement for the slightly less effective effect observed against the UK version of the vaccine.
“This is an incredible achievement that will ensure that we can protect individuals in the UK and the rest of the world from this virus,” Dix said in a statement. “Novavax expects to share more details about the results of the UK study as more data becomes available.”
The process in South Africa
In the Phase 2b clinical trial evaluating the vaccine versus placebo in 4400 adult participants from August 2020 to mid-January 2021, investigators reported a 60% (95% CI, 19.9-80.1) efficacy in preventing COVID-19 among participants who were HIV-negative.
Overall, 29 cases were observed in the placebo group and 15 in the NVX-CoV2373 group. Again, only 1 severe case was reported in the placebo group.
In the general population of the study, consisting of both HIV-positive and HIV-negative participants, the investigators reported an efficacy of 49.4% (95% CI, 6.1 – 72.8).
Preliminary sequencing data show that for 27 of the 44 diagnoses observed total of COVID-19, 92.6% of cases were the South African variant.
The investigators pointed out, however, that one third of the enrolled participants were HIV-positive, demonstrating a previous COVID-19 infection at baseline. Pre-trial infections, based on temporal epidemiological data for the evaluated region, indicate that these cases are the original COVID-19 strain.
Whether the current Novavax product could fully protect against the global spread in South Africa is questionable, however, investigators emphasize its value in reducing the severity of COVID-19.
“The 60% reduced risk of COVID-19 disease in vaccinated people in South Africans emphasizes the value of this vaccine to prevent the extremely worrying disease currently circulating in South Africa and spreading globally,” he said. Principal Investigator Shabir Maddi, executive director of the Wits Infectious Vaccines and Infectious Diseases Research Unit (VIDA), said in a statement. “This is the first COVID-19 vaccine for which we now have objective evidence that it protects against the dominant variant in South Africa.”
US Trial
According to Novavax, the PREVENT-19 enrollment clinical trial in the US and Mexico has already randomized more than 16,000 participants, with expectations of 30,000 enrollments targeted by early February.
Carried out in support of federal agencies, including Operation Warp Speed (OWS), phase 3, randomized, placebo-controlled, observer-orbit evaluation will evaluate the efficacy, safety, and immunogenicity of NVX-CoV2373 with Matrix-M in adults versus placebo.
Johnson & Johnson
Johnson & Johnson (J&J) announced today that the JNJ-78436735 COVID-19 vaccine was 85% effective in preventing severe disease in all regions studied – 28 days after vaccination.
These regions included the USA, Latin America and South Africa. The efficacy against severe disease increased over time, with no cases in vaccinated participants reported after day 49 in all adults 18 years of age and older.
In addition, the level of vaccine protection against moderate to severe COVID-19 infection was 72% in the United States, 66% in Latin America, and 57% in South Africa – 28 days after vaccination.
The single-dose investigational vaccine, which is being developed by Johnson & Johnson’s Janssen pharmaceutical companies, is more commonly referred to as the Ad26.COV2.S vaccine and is a recombinant vector code that is incompetent for serotype 26 (Ad26) adenovirus. a full-length, stabilized SARS-CoV-2 protein (S).
These topline results with a single vaccine COVID-19 vaccine candidate is a promising moment. The potential to significantly reduce the burden of severe disease by providing an effective and well-tolerated vaccine with a single immunization is a critical component of the global public health response, ”said Johnson & Johnson, Executive Committee Vice President and Chief Scientific Officer Paul Stoffels, MD, said. “A single vaccine is considered by the World Health Organization to be the best option in pandemic settings, improving access, distribution and compliance. Eighty-five percent effectiveness in preventing severe COVID-19 disease and preventing COVID-19-related medical interventions will potentially protect hundreds of millions of people from the serious and fatal outcomes of COVID-19. It also offers hope to help ease the huge burden placed on health systems and communities. ”
These results come from the company’s Ensemble study, conducted in eight countries and three regions.
“The J&J vaccine is turning into a fantastic result,” said former FDA Commissioner Scott Gottlieb, MD. posted on Twitter this morning. “We now have 3 extremely effective vaccines. This vaccine has shown sustained (and growing!) Immune protection over time, perhaps from a robust early induction of memory immune cells (CD4 and CD8). The protection was strong and durable. ”