AstraZeneca’s coronavirus disease 2019 (COVID-19) phase 1/2 vaccine trial has shown promising results, according to a study published in The Lancet

COVID-19 has infected more than 14 million people and has caused more than 600,000 deaths according to the World Health Organization. The trail, which was led by Oxford University, found that AZD1222 was well tolerated and generated a robust immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in all evaluated participants.

The trial, known as COV001, is a blinded, multi-center randomized controlled study composed of 1077 healthy adults between the ages of 18 and 55 years. The participants received a single dose of AZD1222 and 10 of the participants received 2 doses a month apart. The study assessed a single dose of AZD1222 against MenACWY, a comparator meningococcal conjugate vaccine, according to a press release. 

The study found that a single dose of AZD1222 resulted in a 4-fold increase in antibodies to the SARS-CoV-2 virus in 95% of participants 1 month after injection. There was a T-cell response in all participants that peaked by day 14 and maintained 2 months after injection. Neutralizing activity against SARS-CoV-2 was seen in 91% of participants 1 month after injection. According to the press release, results were even better in those who had received 2 doses, with 100% of participants showing neutralizing activity against the virus 1 month after injection. 

The vaccine was also well tolerated, with no severe adverse effects (AEs) reported. Common AEs included temporary injection site pain and tenderness, mild-to-moderate headache, fatigue, chills, and feverishness. Reactions were lessened with the pain killer prophylactic paracetamol. Reactions were less frequent after the second dose, according to the press release.  

“The interim phase 1/2 data for our coronavirus vaccine shows that the vaccine did not lead to any unexpected reactions and had a similar safety profile to previous vaccines of this type. The immune responses observed following vaccination are in line with what we expect will be associated with protection against the SARS-CoV-2 virus, although we must continue with our rigorous clinical trial program to confirm this. We saw the strongest immune response in participants who received two doses of the vaccine, indicating that this might be a good strategy for vaccination,” co-author of the trial and chief investigator of the Oxford Vaccine Trial at Oxford University Professor Andrew Pollard, PhD, said in the press release. 

According to the release, late-stage phase 2/3 trials are underway in the United Kingdom, Brazil, and South Africa. They are also due to start in the United States. The late-stage trial will measure the safety and immune response in different age ranges and at various doses. It will also measure how well the vaccine protects recipients against COVID-19. 

Reference:
COVID-19 vaccine AZD1222 showed robust immune responses in all participants in Phase I/II trial (News Release), Cambridge, United Kingdom, July 20, 2020, AstraZeneca, accessed July 20, 2020