Novavax announced that their NVX-CoV2373, a protein-based COVID-19 vaccine candidate, met the primary endpoint, with a vaccine efficacy of 89.3%, in its Phase 3 clinical trial conducted in the United Kingdom (UK). The study assessed efficacy during a period with high transmission and with a new UK variant strain of the virus emerging and circulating widely.
However, in South Africa things were a bit different.
In the South Africa Phase 2b clinical trial, 60% efficacy (95% CI: 19.9 – 80.1) for the prevention of mild, moderate and severe COVID-19 disease was observed in the 94% of the study population that was HIV-negative. Twenty-nine cases were observed in the placebo group and 15 in the vaccine group. One severe case occurred in the placebo group and all other cases were mild or moderate. The clinical trial also achieved its primary efficacy endpoint in the overall trial population, including HIV-positive and HIV-negative subjects (efficacy of 49.4%; 95% CI: 6.1 – 72.8).
This study enrolled over 4,400 patients beginning in August 2020, with COVID-19 cases counted from September through mid-January. During this time, the triple mutant variant, which contains three critical mutations in the receptor binding domain (RBD) and multiple mutations outside the RBD, was widely circulating in South Africa. Preliminary sequencing data is available for 27 of 44 COVID-19 events; of these, 92.6% (25 out of 27 cases) were the South Africa escape variant.
Importantly in this trial, approximately 1/3 of the patients enrolled (but not included in the primary analyses described above) were seropositive, demonstrating prior COVID-19 infection at baseline. Based on temporal epidemiology data in the region, the pre-trial infections are thought to have been caused by the original COVID-19 strain (i.e., non-variant), while the subsequent infections during the study were largely variant virus. These data suggest that prior infection with COVID-19 may not completely protect against subsequent infection by the South Africa escape variant, however, vaccination with NVX-CoV2373 provided significant protection.
“The 60% 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. This is the first COVID-19 vaccine for which we now have objective evidence that it protects against the variant dominating in South Africa,” says 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. “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.”
About the Vaccine -
NVX-CoV2373 is a protein-based vaccine candidate engineered from the genetic sequence of SARS-CoV-2. NVX-CoV2373 was created using Novavax’ recombinant nanoparticle technology to generate antigen derived from the coronavirus spike (S) protein and is adjuvanted with Novavax’ patented saponin-based Matrix-M™ to enhance the immune response and stimulate high levels of neutralizing antibodies. NVX-CoV2373 contains purified protein antigen and can neither replicate, nor can it cause COVID-19. Over 37,000 participants have participated to date across four different clinical studies in five countries. NVX-CoV2373 is currently being evaluated in two pivotal Phase 3 trials: a trial in the U.K that completed enrollment in November and the PREVENT-19 trial in the U.S. and Mexico that began in December.
Novavax initiated development of new constructs against the emerging strains in early January and expects to select ideal candidates for a booster and/or combination bivalent vaccine for the new strains in the coming days.
PS:
Note that Johnson & Johnson’s Janssen Pharmaceutical Companies announced on Jan. 29 that its one-shot COVID-19 vaccine is 66% effective in protecting against disease, but 85% effective against preventing severe disease—results that could make it especially valuable in the effort to vaccinate parts of the world with weak health care systems.
Janssen’s vaccine relies on a more traditional approach: it uses a harmless human cold virus to deliver a SARS-CoV-2 gene to the human immune system. Also Janssen’s vaccine can also be stored in normal refrigerators.
However, in South Africa things were a bit different.
In the South Africa Phase 2b clinical trial, 60% efficacy (95% CI: 19.9 – 80.1) for the prevention of mild, moderate and severe COVID-19 disease was observed in the 94% of the study population that was HIV-negative. Twenty-nine cases were observed in the placebo group and 15 in the vaccine group. One severe case occurred in the placebo group and all other cases were mild or moderate. The clinical trial also achieved its primary efficacy endpoint in the overall trial population, including HIV-positive and HIV-negative subjects (efficacy of 49.4%; 95% CI: 6.1 – 72.8).
This study enrolled over 4,400 patients beginning in August 2020, with COVID-19 cases counted from September through mid-January. During this time, the triple mutant variant, which contains three critical mutations in the receptor binding domain (RBD) and multiple mutations outside the RBD, was widely circulating in South Africa. Preliminary sequencing data is available for 27 of 44 COVID-19 events; of these, 92.6% (25 out of 27 cases) were the South Africa escape variant.
Importantly in this trial, approximately 1/3 of the patients enrolled (but not included in the primary analyses described above) were seropositive, demonstrating prior COVID-19 infection at baseline. Based on temporal epidemiology data in the region, the pre-trial infections are thought to have been caused by the original COVID-19 strain (i.e., non-variant), while the subsequent infections during the study were largely variant virus. These data suggest that prior infection with COVID-19 may not completely protect against subsequent infection by the South Africa escape variant, however, vaccination with NVX-CoV2373 provided significant protection.
“The 60% 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. This is the first COVID-19 vaccine for which we now have objective evidence that it protects against the variant dominating in South Africa,” says 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. “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.”
About the Vaccine -
NVX-CoV2373 is a protein-based vaccine candidate engineered from the genetic sequence of SARS-CoV-2. NVX-CoV2373 was created using Novavax’ recombinant nanoparticle technology to generate antigen derived from the coronavirus spike (S) protein and is adjuvanted with Novavax’ patented saponin-based Matrix-M™ to enhance the immune response and stimulate high levels of neutralizing antibodies. NVX-CoV2373 contains purified protein antigen and can neither replicate, nor can it cause COVID-19. Over 37,000 participants have participated to date across four different clinical studies in five countries. NVX-CoV2373 is currently being evaluated in two pivotal Phase 3 trials: a trial in the U.K that completed enrollment in November and the PREVENT-19 trial in the U.S. and Mexico that began in December.
Novavax initiated development of new constructs against the emerging strains in early January and expects to select ideal candidates for a booster and/or combination bivalent vaccine for the new strains in the coming days.
PS:
Note that Johnson & Johnson’s Janssen Pharmaceutical Companies announced on Jan. 29 that its one-shot COVID-19 vaccine is 66% effective in protecting against disease, but 85% effective against preventing severe disease—results that could make it especially valuable in the effort to vaccinate parts of the world with weak health care systems.
Janssen’s vaccine relies on a more traditional approach: it uses a harmless human cold virus to deliver a SARS-CoV-2 gene to the human immune system. Also Janssen’s vaccine can also be stored in normal refrigerators.
