Carlos III Health Institute, a state-backed institute in Spain, says people administered with first dose of AstraZeneca plc (NASDAQ: AZN) and second dose of Pfizer Inc (NYSE: PFE) drug demonstrated improved safety and effectiveness against COVID-19. 

Increases IgG antibodies in the bloodstream

According to the outcome of the Combivacs study conducted by Carlos III Health Institute, people, who received the first dose of the AstraZeneca vaccine followed by Pfizer’s drug, demonstrated 30 to 40% higher IgG antibodies in their bloodstream. It is a significant achievement compared to people, who received two doses of the AstraZeneca vaccine.

People, who received Pfizer drug as a second dose, demonstrated a significant increase of neutralizing bodies than those who received AstraZeneca vaccine as a second dose. 

Carlos III included 670 people aged between 18 and 59 years, who are administered with the first dose of the AstraZeneca vaccine, in the clinical trial. It administered Pfizer drug to 450 people in the clinical study.

The institute observed side effects like general malaise, headache, and muscle pain in just 1.8% of the participants. However, these symptoms are not severe according to Dr. Magdalena Campins.

A study conducted in the UK involving a mix of AstraZeneca and Pfizer vaccines (first doze AstraZeneca Vaccine and second dose Pfizer drug or vice versa) showed moderate or mild symptoms like chills or headaches compared to receiving two doses of the same type of vaccine. A read-out of the immune responses is expected soon.

Spain entrusted the clinical study to Carlos III Health Institute to find how to proceed after it limited the AstraZeneca dose to people aged above 60 years on concerns of blood clots in younger people.

Following the widespread news of blot clots, younger people, who received the first dose of the AstraZeneca vaccine, are excluded from receiving the second dose of the AstraZeneca vaccine. 

Pfizer to supply 1.8 billion doses of comirnaty

BioNTech SE and Pfizer signed a deal with EC (European Commission) on May 20, 2021. As per the terms of the agreement, both the companies will supply 900 million COMIRNATY doses to the EU. 

EU has an option to request additional 900 million doses from these firms. The new agreement is in addition to the previous commitment of 600 million doses to the EU in 2021.