the staff of the Ridgewood blog
Ridgewood NJ, two studies were published in The Lancet, describing results of clinical trials for candidate vaccines from China and the UK. The candidate from Chinese pharmaceutical manufacturer CanSino is a single-dose vaccine that utilizes a recombinant adenovirus vector. The associated trial was a randomized, double-blind, placebo-controlled Phase 2 trial that involved 508 healthy human volunteers in Wuhan, China. Two dosages were tested, and both demonstrated high seroconversion after 4 weeks (96% and 97%, respectively) and significant neutralizing antibody response. Severe adverse reactions were reported in 9% of those receiving the higher dose and 1% of those receiving the lower dose, a statistically significant difference. Based on these results, the researchers intend to conduct a Phase 3 trial for the lower vaccine dose in the near future.
The candidate from the UK utilizes a chimpanzee adenovirus vector, created through a collaboration between Oxford University and AstraZeneca. The randomized Phase 1/2 trial was single-blinded and utilized a meningococcal conjugate vaccine as a control. The researchers administered the candidate vaccine to 543 healthy adults—533 receiving a single dose and 10 receiving a prime-boost formulation. No serious adverse reactions were reported, and adverse events were reduced among individuals who also received paracetamol (also known as acetaminophen) prohpylactically. The results indicate that the vaccine induced both T-cell and anti-spike IgG immune responses, and the anti-spike IgG response increased following the boost vaccination among those who received it. Neutralizing antibody responses were detected in 91% of individuals after a single dose—and 100% of individuals following the booster dose, for those who received it. According to the researchers, “these results…support large-scale evaluation of this candidate vaccine in an ongoing phase 3 programme.”
The UK government announced that it reached an agreement with multiple pharmaceutical companies to secure 90 million doses of candidate vaccines. This includes 30 million doses of an mRNA vaccine from BioNTech and Pfizer as well as 60 million doses of an inactivated whole-virus vaccine from Valneva (with an option to acquire an additional 40 million doses from Valneva). The UK government also secured 1 million doses of neutralizing antibodies from AstraZeneca for immunocompromised individuals who may not be able to receive a vaccination due to concerns about potential adverse events.