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Is AstraZeneca and Oxford’s COVID vaccine safe? Australia prefers Pfizer vaccine

Updated: Apr 10, 2021

Australia prefers Pfizer vaccine, US agency raises concerns over the information released by AstraZeneca, EMA’s safety committee says the vaccine is safe

Australian ATAGI prefers Pfizer vaccine over AstraZeneca's vaccine

Australian Technical Advisory Group on Immunization (ATAGI) has noted further evidence of rare but severe thrombosis with the COVID-19 vaccine of AstraZeneca.

ATAGI has recommended the use of Pfizer's COVID-19 vaccine over AstraZeneca's vaccine in adults aged under 50 years. In older adults, the benefits of the vaccine outweigh the risks; however, the agency recommended informing the patients about the risks. The second dose can be administered for patients who had no severe adverse events with the first dose.

AstraZeneca and Oxford's COVID-19 vaccine causes' thrombosis with thrombocytopenia syndrome (TTS), a severe condition with blood clots in the brain or the other parts of the body.

Further recently, on 7th April 2021, European Medicines Agency has confirmed the relationship between the use of AstraZeneca's vaccine and thrombosis with thrombocytopenia.

US’s DSMB raised concerns regarding the information released by AstraZeneca

USA’s Data and Safety Monitoring Board (DSMB) raised concerns regarding the data submitted by AstraZeneca, saying that the data was ‘outdated,’ showing incomplete efficacy information of the vaccine.

The board has recommended the company work in collaboration with DSMB to update the efficacy data.

In response, AstraZeneca has announced that the data was based on pre-specified interim analysis. Further, AstraZeneca has announced that it will submit the primary analysis with the most updated efficacy data.

EMA’s Pharmacovigilance Risk Assessment Committee concluded that the Vaxzevria do not increase the risk of blood clots

The PRAC has recommended the inclusion of more information in the product information. Further, EMA has announced that the PRAC is assessing the reported cases.

On 29th March, EMA is convening an expert group, including experts in hematology, cardiovascular diseases, infectious diseases, virology, neurology, and epidemiology. The meeting discusses the plausible mechanism of action, risk factors, and any additional data required for understanding the risks and reported blood clots.

On 18th March 2021, PRAC reported that the vaccine was associated with sporadic cases of blood clots associated with thrombocytopenia, including rare instances of clots in the blood vessels draining the blood from the brain. Further, it added that 20 million patients were administered the vaccine in the UK and EMA; only seven blood clots and 18 cases of CVST were reported. The majority of the shots were administered in the UK (11 million). But EMA raised concerns regarding the blood clots in the younger population.

The vaccine is safe and efficacious, as per experts. However, the outdated data raises concerns.

Canada's NACI recommended not to use AZ's vaccine in people under 55 years

Canada has suspended the use of AstraZeneca and Oxford's vaccine in people under 55 years because of the rare blood clot reports. The recommendation is based on the blood clot reports observed in the European population, especially in younger women.

Most of the clots were reported within 14 days of administering the vaccine and are reported in the younger patients.

In older patients, vaccines' benefits outweigh the risks, so the vaccine is recommended in the more aging population.


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