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Novavax, J&J Return Mixed Covid-19 Vaccine Results

Syringe and three vials

(Arek Socha, Pixabay)

29 Jan. 2021. Results from international clinical trials show largely favorable results for two Covid-19 vaccines, but still limitations against the South African variant. Johnson & Johnson reported the findings this morning from its trials in the U.S., Latin America, and South Africa, while Novavax reported results yesterday from its U.K. and South Africa trials. Neither set of results is peer-reviewed.

Vaccine and adjuvant, two doses, 21 days apart

Novavax is testing its vaccine candidate code-named NVX-CoV2373, made with a technology that generates nanoscale particles of synthetic proteins designed specifically against the genetic code of their targets. In this case, the target is the protein on the surface of the SARS-CoV-2 virus’s spike that penetrates and infects host cells. The vaccine is combined with the company’s vaccine adjuvant called Matrix-M, an additive that boosts immune responses, allowing for lower doses of the primary vaccine. Novavax is testing NVX-CoV2373 in late- or mid-stage trials in the U.K., South Africa, U.S., and Mexico.

The company’s trial in the U.K. enrolled some 15,000 participants, age 18 and over, receiving two doses of NVX-CoV2373 plus Matrix-M, or a placebo, 21 days apart. After seven days following the second injection, 56 cases of Covid-19 symptoms appeared in the placebo group, compared to six cases among active vaccine recipients, an efficacy rate of 89 percent. That efficacy rate was somewhat lower for the B.1.1.7 or U.K. variant of Covid-19 at 86 percent, compared to 96 percent for the original Covid-19 version. And except for one severe case among placebo recipients, all individuals with Covid-19 disease exhibited mild or moderate symptoms.

Novavax’s South Africa trial is a mid-stage study enrolling 4,400 participants. Like the U.K. trial, participants are randomly assigned to receive two doses of NVX-CoV2373 plus Matrix-M, or a placebo, but the study team is also comparing participants testing positive or negative for HIV. South Africa has one of the highest HIV infection rates in the world. The company says six percent of trial participants were HIV-positive.

The results show 15 participants receiving NVX-CoV2373 plus Matrix-M reported Covid-19 symptoms, compared to 29 placebo recipients, an efficacy rate of 49 percent. Some 90 percent of participants experiencing symptoms were infected with the B.1.35 or South African variant of Covid-19. Among participants not infected with HIV, the Covid-19 efficacy rate is 60 percent.

Novavax says it started work on a booster or combination vaccine to address the new SARS-CoV-2 variants. “A primary benefit of our adjuvanted platform is that it uses a very small amount of antigen,” says Novavax’s R&D chief Gregory Glenn in a company statement, “enabling the rapid creation and large-scale production of combination vaccine candidates that could potentially address multiple circulating strains of Covid-19.”

Johnson & Johnson vaccine less effective, but one shot

The Johnson & Johnson vaccine is made by the company’s Janssen Pharmaceutical subsidiary and designed as a one-shot vaccine, compared to most others that require two doses. The Janssen vaccine technology uses an engineered adenovirus, a benign virus that’s become a workhorse for gene therapies, to deliver antigen proteins. In this case, the J&J vaccine code-named Ad26.COV2.S, is designed to induce the immune system to produce antibodies and T-cells to attack SARS-CoV-2 viruses.

The company’s late-stage trial enrolled 44,325 participants at 228 sites in the U.S., Mexico, Brazil, Chile, Colombia, Peru, and South Africa, with participants randomly assigned to receive Ad26.COV2.S or a placebo. However, J&J defines its efficacy rate as prevention of moderate to severe Covid-19 symptoms, while trials from other companies generally use prevention of all symptoms to define efficacy.

Overall, says J&J, Ad26.COV2.S showed an efficacy rate of 66 percent, with the U.S. reporting 72 percent efficacy, Latin America at 66 percent, and South Africa at 57 percent. For prevention of severe disease symptoms, the overall efficacy is 85 percent, with no cases of vaccine recipients dying or needing hospitalization after 28 days. J&J says nearly all cases of Covid-19 disease in South Africa were from the B.1.35 variant.

“Changing the trajectory of the pandemic,” says Janssen Pharmaceuticals’ R&D chief Mathai Mammen in a J&J statement, “will require mass vaccination to create herd immunity, and a single-dose regimen with fast onset of protection and ease of delivery and storage provides a potential solution to reaching as many people as possible. The ability to avoid hospitalizations and deaths would change the game in combating the pandemic.”

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Disclosure: The author owns shares in Johnson & Johnson

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