AstraZeneca COVID-19 vaccine

AstraZeneca COVID-19 Vaccine

The AstraZeneca COVID-19 vaccine, also known as Vaxzevria, is a viral vector vaccine developed by AstraZeneca in collaboration with the University of Oxford. It is designed to provide immunity against the SARS-CoV-2 virus, which causes COVID-19.

Development and Approval

The vaccine was developed using a modified chimpanzee adenovirus vector, known as ChAdOx1, which carries the genetic code for the spike protein of the SARS-CoV-2 virus. This approach aims to stimulate an immune response without causing the disease itself.

The vaccine received its first emergency use authorization in the United Kingdom in December 2020, followed by approvals in various countries and by the World Health Organization (WHO) for emergency use listing.

Mechanism of Action

The AstraZeneca vaccine works by introducing the genetic material of the SARS-CoV-2 spike protein into the body. The immune system recognizes this protein as foreign and mounts an immune response, producing antibodies and activating T-cells. This prepares the immune system to fight the actual virus if the person is exposed in the future.

Efficacy

Clinical trials have shown that the AstraZeneca vaccine has an efficacy rate of approximately 70% after two doses. The efficacy can vary based on the interval between doses, with longer intervals showing higher efficacy rates.

Dosage and Administration

The vaccine is administered in two doses, typically 4 to 12 weeks apart. It is given as an intramuscular injection, usually in the upper arm.

Side Effects

Common side effects include pain at the injection site, fatigue, headache, muscle pain, chills, fever, and nausea. Rare side effects include blood clotting events, which have been investigated and monitored by health authorities.

Storage and Distribution

One of the advantages of the AstraZeneca vaccine is its storage requirements. It can be stored at normal refrigerator temperatures (2-8°C), making it easier to distribute, especially in low-resource settings.

Global Impact

The AstraZeneca vaccine has been a crucial tool in the global fight against COVID-19, particularly in low- and middle-income countries. It is part of the COVAX initiative, which aims to ensure equitable access to COVID-19 vaccines worldwide.

Controversies and Challenges

The vaccine has faced challenges, including concerns over rare blood clotting events and varying efficacy against different variants of the virus. These issues have led to changes in recommendations and usage in some countries.

See Also

• COVID-19 vaccine
• Pfizer-BioNTech COVID-19 vaccine
• Moderna COVID-19 vaccine
• Johnson & Johnson COVID-19 vaccine

References

• WHO: The Oxford/AstraZeneca COVID-19 vaccine: what you need to know
• AstraZeneca and Oxford University announce landmark agreement for COVID-19 vaccine

External Links

• AstraZeneca Official Website
• University of Oxford Official Website