Recent data releases from Novavax and Johnson & Johnson on 2019 coronavirus disease vaccines (COVID-19) demonstrate efficacy, but some concern remains about new variants becoming more common recently.
Protein-based Coronavirus 2019 (COVID-19) vaccine NVX-CoV2373, from Novavax, has reported phase 3 findings showing an efficacy of 89.3% in the prevention of COVID-19 in UK participants.
The findings of the study – conducted at a time of significant transmission in the country and an emerging, more transmissible variant spreading globally – coincide with the findings from Phase 2b that show less prevention of the variant originally found in South Africa. Africa was observed.
The vaccine
NVX-CoV2373 is a vaccine consisting of a full-length prefusion spike protein made from proprietary recombinant nanoparticle technology and the saponin-based Matrix-M adjuvant.
The purified protein is produced in insect cells and encoded by the genetic sequence of the SARS-CoV-2 spike protein.
With the emergence of new mutant strains of SARS-CoV-2 in regions including South East England and South Africa, Novavax has begun to develop new vaccine constructs specified according to the genetic codes of the strains, with the expectation that ideal candidates are delivered via booster or in combination as a bivalent vaccine will become apparent in the coming days.
Testing for these newer vaccines is expected to start in the second quarter of 2021.
“A primary advantage of our adjuvanted platform is that it uses a very small amount of antigen, allowing for the rapid creation and large-scale production of candidate combination vaccines that could potentially target multiple circulating strains of COVID-19,” said Gregory M. Glenn , MD, Novavax president of Research and Development, in a statement.
UK Trial
Researchers enrolled more than 15,000 adult participants aged 18-84 years to evaluate the vaccine for the primary endpoint of the occurrence of PCR-confirmed symptomatic COVID-19 with onset at least 7 days after the booster vaccine dose in participants who Serologically negative for SARS-CoV-2 at baseline.
More than a quarter (27%) of the trial participants were older than 65 years.
In the first interim analysis of 62 COVID-19 cases, 56 (89.2%) were observed in the placebo group versus only 6 in the vaccine group (95% CI, 75.2-95.4). Of the 62 cases, only 1 was serious – from a placebo patient.
The highly transmissible British variant strain was detected in more than half of all observed cases, researchers noted (n = 32). In a post-hoc review, researchers reported that NVX-CoV2373 was 95.6% effective against the original COVID-19 strain and 85.6% against the UK variant strain.
In an interim analysis of the safety database, researchers observed low, balanced rates of serious and medically-attended adverse events in both treatment arms.
Clive Dix, Chair, of the UK Vaccine Task Force, praised the results as “spectacular” and encouraged the slightly less effective effect seen with the vaccine against the British variant.
“This is an incredible achievement that will allow us to protect individuals in the UK and around the world from this virus,” Dix said in a statement. “Novavax expects to share further details of the UK study results as additional data becomes available.”
South Africa Trial
In the Phase 2b clinical trial evaluating vaccine versus placebo in more than 4,400 adult participants from August 2020 to mid-January 2021, researchers reported a 60% (95% CI, 19.9-80.1) prevention of COVID-19 among participants who were HIV negative.
In total, they observed 29 cases in the placebo group and 15 in the NVX-CoV2373 group. Again, only 1 serious case was reported in the placebo group.
In the total trial population, consisting of both HIV-positive and HIV-negative participants, the researchers reported an efficacy of 49.4% (95% CI, 6.1 – 72.8).
Preliminary sequence data shows that for 27 of the 44 total COVID-19 diagnoses observed, 92.6% of the cases were the South African variant.
However, researchers emphasized that one-third of enrolled participants were HIV-positive, demonstrating prior COVID-19 infection at baseline. Pre-study infections, by transient epidemiological data for the region assessed, indicate that these cases would be the original COVID-19 strain.
Whether the current Novavax product could fully protect against the globally distributed variant in South Africa is questionable, but researchers stress its value in reducing the severity of COVID-19.
“The 60% reduced risk of COVID-19 disease in vaccinated individuals in South Africans underscores the value of this vaccine in preventing disease of the very worrying variety currently circulating in South Africa and spreading worldwide,” said lead researcher professor. Shabir Maddi, executive director of the Vaccines and Infectious Diseases Analytics Research Unit (VIDA) at Wits, said in a statement. “This is the first COVID-19 vaccine for which we now have objective evidence to protect against the variant that dominates South Africa.”
American trial
According to Novavax, the PREVENT-19 clinical trial in the US and Mexico has already randomized more than 16,000 participants, with an expectation of 30,000 targeted enrollments in early February.
The Phase 3, randomized, placebo-controlled, observer-blind review, conducted in support of federal agencies, including Operation Warp Speed (OWS), will measure 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 is 85 percent effective in preventing serious disease in all regions studied – 28 days after vaccination.
These regions include the US, Latin America and South Africa. Efficacy against serious diseases increased over time with no cases reported in vaccinated participants after Day 49 in all adults 18 years and older.
In addition, the vaccine’s level of 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, being developed by the Janssen Pharmaceutical Companies of Johnson & Johnson, is more commonly referred to as the Ad26.COV2.S vaccine and is a recombinant, replication-incompetent adenovirus serotype 26 (Ad26) vector encoding a stabilized full length SARS-CoV-2 spike (S) protein.
“These topline results with a single-shot COVID-19 vaccine candidate 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 part of the global public health response, ”Johnson & Johnson Vice Chairman of the Executive Committee 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 situations, improving access, distribution and compliance. Eighty-five percent efficacy 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 consequences of COVID-19. It also offers hope to help ease the tremendous burden on health care systems and communities. “
These results come from the company’s Ensemble study conducted in eight countries and three regions.
“The J&J vaccine is producing a fantastic result,” said former FDA Commissioner Scott Gottlieb, MD. tweeted this morning. “We now have 3 highly effective vaccines. This vaccine has shown sustained (and increasing!) Immune protection over time, perhaps due to robust early induction of memory immune cells (CD4 and CD8). The protection was strong and durable. “