Science Re-Views: What you need to know about the promising Oxford-AstraZeneca COVID-19 vaccine

I would like to share here the positive results from one of the promising SARS-COVID-2 vaccines labelled AZD1222, and explain more about the clinical trial process.

Currently, more than 140 vaccines for COVID-19 are in pre-clinical and clinical development, which means that they are being tested in non-human subjects (cells, mice, rats, ferrets, rhesus macaques, etc). 10 vaccines are being tested in humans for safety and dosages (this means in healthy subjects), 8 vaccines are in phase II, which involves testing the safety in expanded studies. Only 3 vaccines are starting phase III, meaning large scale efficacy tests. In this phase, the vaccine is tested in thousands of people separating the volunteers in 2 groups: one will receive the actual vaccine and the other - the placebo one to determine if the vaccine protects against the coronavirus. The last step can be a phase IV trial with an even bigger and diverse group of volunteers and a review of the results by the local regulatory entity which will evaluate if the vaccine is approved or not for use in that region. Notice that each country has its own regulatory organization and some medicines are approved for use in the USA but not in Europe. Fortunately, there are a lot of different types of vaccines and you CAN NOT put them all in the same bag!

These vaccines use a different type of virus that wouldn’t affect humans in a negative way (called a vector) to deliver coronavirus genes into cells and trigger an immune response.

The British-Swedish company AstraZeneca and the University of Oxford are working on a viral vector vaccine using a chimpanzee adenovirus that will expose the coronavirus’ S protein on its surface in order to trigger an immune system response in the people that will be vaccinated. The vaccine is in Phase II/III trial in the UK and Phase III trials in Brazil and South Africa, and it might be ready by 2021. “AstraZeneca” claimed their total manufacturing capacity stands at two billion doses. This vaccine uses a different type of virus that wouldn’t affect humans in a negative way (called a vector) to deliver coronavirus genes into cells and trigger an immune response.

They reported last Monday the "encouraging" results from the trial that included 1,077 participants from 18 to 55 years old (who had not previously tested positive for the coronavirus). The participant's gender was fairly well distributed, but they were mostly white. The study was single-blind, meaning patients did not know whether they received the coronavirus vaccine or the control (a meningitis vaccine).

They reported that around 70% of the participants suffered adverse events such as pain, feeling feverish, chills, muscle ache, headache, and malaise, which were reduced by the use of paracetamol, and there were no serious adverse events related to the vaccine. The T-cell immune responses peaked on day 14 and the antibody response rose by day 28. Neutralising antibody responses against SARS-CoV-2 were detected in 91% of participants. After a second vaccine application, called boost, this number rose to 100%. After a booster dose, all participants had neutralising activity.

Just a friendly reminder: we should be grateful for the existence of vaccines that have helped prevent the spread of terrible diseases, such as tuberculosis and polio. Both brought huge suffering in multiple countries around the world and were controlled thanks to the implementation of vaccines!

I encourage you to check on the links below and learn more about the different vaccines and the research behind them. Be aware of your own cognitive bias, for example, stop citing the inexistent connection between autism and vaccines, that research has now been thoroughly debunked, the Lancet journal issued a retraction on Wakefield’s paper, and he lost his medical licence.

Let me leave you with this great advice from the WHO about how to respond to vaccine deniers:

“Vaccine-preventable diseases can be very severe, and still cause millions of deaths per year around the world. Even with the best available care in the world, vaccine-preventable diseases can cause permanent disability and even death. Prevention is by far the best intervention.”

“There are no equally safe and effective alternatives to vaccinations.”

“The scientific evidence is clear: vaccination is the most effective health intervention for prevention of many serious diseases.”

“We as an institution/agency are aiming to sustain the health of every individual member of the public. We are sorry that you have lost trust in our effort, but we hope to regain it.”

“The scientific evidence is clear; vaccination is a safe way to prevent many serious diseases. Any theoretical risk to the individual and society is far outweighed by the risks to one and all of not doing so.“