FAST FACTS: What you need to know about the AstraZeneca vaccine


Posted at Mar 04 2021 08:25 PM

FAST FACTS: What you need to know about the AstraZeneca vaccine 1
Nearly a half million doses of AstraZeneca’s vaccines arrived in the country Thursday night, making it the 2nd COVID-19 vaccine brand to be distributed domestically. Palace photo

MANILA — More than 400,000 doses of AstraZeneca’s vaccines arrived in the Philippines on Thursday evening, making it the 2nd COVID-19 vaccine brand to be distributed in the country.

Here’s what you need to know about AstraZeneca’s vaccine:


The COVID-19 Vaccine (ChAdOx1-S[recombinant]) or AZD1222 vaccine was developed by the British pharmaceutical company AstraZeneca and the Oxford University.

It has an efficacy rate of 63.09% against symptomatic COVID-19 infection, according to the World Health Organization, which included AstraZeneca in its emergency use listing.

The Philippine Food and Drug Administration said it has an overall efficacy rate of 70% after the first dose and trials are ongoing to determine the efficacy rate after the 2nd dose.

The emergency use authorization document from the FDA states that it comes in two doses of 0.5 mL each, with the 2nd dose given between 4 to 12 weeks after the first dose.

Despite concerns that AstraZeneca’s vaccine like others is less effective against new variants, the WHO said its Strategic Advisory Group of Experts (SAGE) still recommends its use.

A WHO Philippines official said a study claiming that the AstraZeneca vaccine is only 10% effective against the South African variant has a very limited sample size and that it should not be a cause of concern for now since the country only has a few detected cases.

The official also pointed out that while no vaccine is proven to prevent the transmission of COVID-19, the priority now is to reduce severe cases and deaths, something that AstraZeneca is said to be able to do.


Unlike Sinovac’s vaccine, AstraZeneca’s can be administered to the elderly and those with pre-existing medical conditions. However, it is not yet recommended to those below the age of 18.

Because it can be used on the elderly, vaccine czar Secretary Carlito Galvez Jr. said senior health care workers will be prioritized in the first batch of AstraZeneca’s vaccines. 

The WHO emphasized that the AstraZeneca vaccines coming from the COVAX Facility, a vaccine-sharing initiative that aims for equitable distribution of COVID-19 vaccines, should first be given to health workers. Otherwise, there may be access concerns.

“If we cannot demonstrate that we are following this prioritization, unfortunately, the COVAX may have to consider other options where the impact of the vaccine rollout will be more useful and practical and will contribute to saving more lives,” WHO Country Representative Rabindra Abeyasinghe said on Thursday


The AstraZeneca is a viral vector vaccine, which uses a weakened version of a common cold virus (adenovirus) in chimpanzees to carry thegenetic material of the SARS-CoV-2 virus spike protein. Once injected into the body, it allows the production of the spike protein, triggering an immune response that will train the body to fight the disease if the person is infected later on. 

This is different from Sinovac’s inactivated virus vaccine, which contains the killed SARS-CoV-2 virus, or Pfizer’s vaccine using the relatively new messenger RNA technology. 

Unlike mRNA vaccines that require ultra cold freezers, AstraZeneca can be kept in regular refrigerator temperature of 2 to 8 degrees Celsius. The EUA states that the vials should not be frozen. This makes AstraZeneca easier to transport to other parts of the country and to administer.


Besides the 487,200 doses that arrived on Thursday, the WHO said the Philippines “is receiving one of the largest consignment of COVAX vaccines.”

From March to May, the Philippines is expected to receive 4.58 million doses of AstraZeneca’s vaccines.

This does not include the 17 million AstraZeneca doses secured through the government’s tripartite agreements with local government units and the private sector.

There is still no schedule as of posting time on when the next batches of AstraZeneca vaccines will arrive. 

Besides the United Kingdom, AstraZeneca’s vaccine is being used under limited or emergency authorization in countries in Europe, Argentina, Brazil, India, Malaysia, Mexico, and others.

Other COVID-19 vaccines allowed for emergency use in the Philippines are that of Pfizer and Sinovac