AstraZeneca Reports its COVID-19 Vaccine has “Substantial Impact” in Reducing Transmission of the Virus

The company is reporting a reduced transmission after the first and second doses. However, questions are arising on the data around these claims and Switzerland declined to approve the vaccine.

AstraZeneca announced its vaccine, COVID-19 Vaccine AstraZeneca, has the potential to reduce significantly the asymptomatic transmission of the virus. The company reported transmission was reduced by 67% after a single dose, and 50% after the second dose regimen.

“This primary analysis reconfirms that our vaccine prevents severe disease and keeps people out of hospital. In addition, extending the dosing interval not only boosts the vaccine’s efficacy, but also enables more people to be vaccinated upfront.” AstraZeneca Executive Vice President BioPharmaceuticals R&D, Sir Mene Pangalos, said. “Together with the new findings on reduced transmission, we believe this vaccine will have a real impact on the pandemic.”

It is important to note that Switzerland declined approval of the vaccine due to a lack of data.

In a report published in the Financial Times, SwissMedic, the country's regulation body, is awaiting results from 2 clinical trials in North and South America.

"For the vaccine from AstraZeneca, the data available and evaluated to date are not yet sufficient for approval,” SwissMedic said on Wednesday in the report. “In order to obtain additional data on safety, efficacy, and quality, data from new studies are required."

The vaccine was formerly known as AZD1222 and is now referred to as the COVID-19 Vaccine AstraZeneca.

In addition, the company reported an increased efficacy with longer inter-dose interval protection of over 70% starting after the first dose. According to the investigators, during this period of limited vaccine supply, the protection of the AstraZeneca vaccine allows for up to 3 months in the interval between the first dose administered and the second dose.

“ChAdOx1 nCoV-19 vaccination programs aimed at vaccinating a large proportion of the population with a single dose, with a second dose given after a 3 month period is an effective strategy for reducing disease, and may be the optimal for rollout of a pandemic vaccine when supplies are limited in the short term,” the investigators wrote.

A preprint of the study appeared in the journal The Lancet.

The primary analysis of the phase 3 clinical trials comes from the United Kingdom, Brazil, and South Africa.

All 3 of the trials from the various countries were single-blinded, multi-center, and randomized studies assessing the safety, efficacy, and immunogenicity of COVID-19 Vaccine AstraZeneca.

The COV002 trial is a phase 2/3 trial studying 12,390 participants in the UK. Trial participants are ages 18 years or over, who are healthy or have medically stable chronic diseases and are at increased risk for being exposed to the SARS-CoV-2 virus. Participants receive 1 or 2 intramuscular doses of a half dose (~2.5 x1010 viral particles) or full dose (~5x1010 viral particles) of COVID-19 Vaccine AstraZeneca or comparator, meningococcal vaccine MenACWY.

The COV003 is a phase 3 trial studying 10,300 participants in Brazil. Trial participants are 18 years or over, who are healthy or have medically stable chronic diseases and are at increased risk for being exposed to the SARS-CoV-2 virus. Participants are randomized to receive 2 intramuscular doses of a full dose (~5x1010 viral particles) of COVID-19 Vaccine AstraZeneca or comparator, meningococcal vaccine MenACWY as first dose and a saline placebo as second dose.

COV005 is a phase 1/2 trial studying 2,070 participants in South Africa. Trial participants were between the ages of 18-65, who are living with or without HIV, and randomized to receive 2 intramuscular doses of AZD1222 at 5-7.5 x1010 viral particles or saline placebo.

This data comes on the heels of the European Union’s recommendation to grant a commercial marketing authorization to the company for its vaccine last week. This would pave the way for widespread distribution of the COVID-19 Vaccine AstraZeneca across the continent.

“Today’s recommendation underscores the value of AstraZeneca’s COVID-19 vaccine which is not only effective and well-tolerated, but also easy to administer and, importantly, protects fully against severe disease and hospitalizations,” AstraZeneca CEO Pascal Soriot, said last week.

The company said the data will continue to be analyzed and shared with regulators around the world to support their ongoing rolling reviews for emergency supply or conditional approval. AstraZeneca is also seeking emergency use listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income countries.