Recent data released by Novavax and Johnson & Johnson on vaccines against coronavirus 2019 (COVID-19) show effectiveness, but there is still some concern about new variants that have recently become more prevalent.
Novavax’s 2019 protein-based coronavirus NVX-CoV2373 candidate vaccine (COVID-19) reported phase 3 findings showing 89.3% effectiveness in preventing COVID-19 in UK participants.
The trial’s findings – conducted at a time of significant transmission in the country and an emerging, more communicable variant spreading globally – coincide with the findings of phase 2b that show less prevention of the variant originally seen in South Africa.
The vaccine
NVX-CoV2373 is a vaccine composed of a full-length pre-fusion peak protein made from patented recombinant nanoparticle technology and the 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 mutated strains of SARS-CoV-2 in regions including southeastern England and South Africa, Novavax began the development of new vaccine constructions specified for the genetic codes of the strains, with the expectation that the ideal candidates be supplied via booster or in combination as a bivalent vaccine will become apparent in the coming days.
Tests for these new vaccines would be launched in the second quarter of 2021.
“A major benefit of our adjuvant platform is that it uses a very small amount of antigen, allowing for rapid creation and large-scale production of combined candidate vaccines that can potentially target multiple circulating strains of COVID-19,” said Gregory M Glenn, MD, President of Research and Development at Novavax, in a statement.
Test in the UK
Researchers enrolled more than 15,000 adult participants aged 18-84 years of age to assess the vaccine for a primary endpoint of occurrence of symptomatic COVID-19 confirmed by PCR starting at least 7 days after the booster vaccine dose in serologically negative participants for SARS -CoV-2 at baseline.
More than a quarter (27%) of trial participants were over 65 years old.
In the first provisional analysis of 62 cases of COVID-19, 56 (89.2%) were observed in the placebo arm, against only 6 in the vaccine group (95% CI, 75.2 – 95.4). Of the 62 cases, only 1 was severe – from a patient who received a placebo.
The highly transmissible strain of the United Kingdom was detected in more than half of all cases observed, the researchers noted (n = 32). In a post hoc assessment, the researchers reported that NVX-CoV2373 was 95.6% effective against the original COVID-19 strain and 85.6% effective against the United Kingdom variant strain.
In an intermediate analysis of the safety database, the researchers observed low and balanced rates of serious and physician-assisted adverse events in both treatment arms.
Clive Dix, chairman of the UK Vaccine Task Force, praised the results as “spectacular” and expressed encouragement for the slightly less effective effect seen against the UK variant with 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,” said Dix in a statement. “Novavax hopes to share more details about the test results in the UK, as additional data becomes available.”
South Africa Event
In the phase 2b clinical trial that evaluated the vaccine versus placebo in more than 4,400 adult participants from August 2020 to mid-January 2021, the researchers reported an efficacy of 60% (95% CI, 19.9 – 80.1 ) in the prevention of COVID-19 among participants who were HIV-negative.
Overall, they observed 29 cases 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, composed of HIV-positive and HIV-negative participants, the researchers reported an efficacy of 49.4% (95% CI, 6.1 – 72.8).
Preliminary sequencing data show that, for 27 of the 44 diagnoses of COVID-19 observed, 92.6% of cases were of the South African variant.
The investigators emphasized, however, that one-third of the enrolled participants were HIV-positive, demonstrating previous COVID-19 infection at the start of the study. Pre-test infections, based on temporal epidemiological data for the evaluated region, indicate that these cases would be the original COVID-19 strain.
It is questionable whether the current Novavax product could completely protect against the South African variant, which has spread globally, but researchers emphasize its value in reducing the severity of COVID-19.
“The reduced risk of 60% against COVID-19 disease in vaccinated individuals in South Africa underscores the value of this vaccine to prevent disease of the highly worrying variant that currently circulates in South Africa and is spreading globally,” the researcher principal professor Shabir Maddi, the executive director of the Wits Vaccine and Infectious Disease (VIDA) Analytical Research Unit, 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.”
USA Trial
According to Novavax, the PREVENT-19 clinical trial in the US and Mexico has already randomized more than 16,000 participants, with an expected 30,000 applications targeted by the beginning of February.
Conducted in support of federal agencies, including Warp operating speed (OWS), the randomized, placebo-controlled, phase 3 evaluation for the observer will assess the efficacy, safety and immunogenicity of NVX-CoV2373 with Matrix-M in adults versus placebo.
Johnson & Johnson
Johnson & Johnson (J&J) announced today that its JNJ-78436735 COVID-19 vaccine was 85 percent effective in preventing serious illnesses in all regions studied – 28 days after vaccination.
These regions include the USA, Latin America and South Africa. Efficacy against severe illness has increased over time, with no cases in vaccinated participants reported after day 49 in all adults 18 and older.
In addition, the level of protection of the vaccine against moderate to severe COVID-19 infection was 72% in the United States, 66% in Latin America and 57% in South Africa – 28 days post-vaccination.
The experimental single dose 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 adenovirus vector encoding, incompetent for replication, serotype 26 ( Ad26) a complete and stabilized SARS-CoV-2 spike (S) protein.
“These first-line results with a single-shot COVID-19 candidate vaccine represent a promising moment. The potential to significantly reduce the burden of serious illness by providing an effective and well-tolerated vaccine with just one immunization, is a critical component of the global public health response, ”Johnson & Johnson, Executive Committee Vice President and Scientific Director 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. The eighty-five percent effectiveness in preventing serious COVID-19 disease and preventing COVID-19-related medical interventions will potentially protect hundreds of millions of people from serious and fatal COVID-19 results. It also offers the hope of helping to alleviate the enormous 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 has a fantastic result,” former FDA commissioner Scott Gottlieb, MD. tweeted this morning. “We now have 3 highly effective vaccines. This vaccine showed sustained (and growing!) Immune protection over time, perhaps from a robust initial induction of immune memory cells (CD4 and CD8). The protection was strong and durable. “