Pakistan received its first shipment of 1.2 million Oxford-AstraZeneca vaccine shots through the Covid-19 Vaccines Global Access facility earlier this month. As uncertainty surrounds the efficiency and potential consequences of the drug, let’s weigh the benefits and risks of the vaccine.
THE DRUG:
The Oxford-AstraZeneca — also known as AZD1222 — uses a chimpanzee adenovirus vaccine vector. Covid-19 is more economic and efficient as it is less expensive and can be stored in an ordinary fridge, unlike other vaccines that should be kept at very low temperature and are really expensive.
Covid-19 gave us all a difficult time figuring out the treatment and producing vaccination. AstraZeneca is one of the vaccines that target the virus by producing the antigens by triggering the cells.
Antigen’s genetic code is delivered by using a vector which is a modified virus and an immune response is triggered. Natural procedure against infections is mimicked in this vaccine.
AstraZeneca can trigger powerful T cell’s cellular immune response while B cells produce antibodies by the action of vaccine. This vaccine is produced from weakened viruses of common cold or adenovirus taken from Chimpanzees.
HOW DOES IT WORK?
AstraZeneca vaccine is prepared by taking genes from the Covid-19 spike proteins present on the surface and inserting those genes in the harmless virus. Then this virus is inserted into the human body.
This vaccine enters the human body’s cells and produces spike proteins. The immune system of the body is activated because of spike proteins and start producing antibodies by B cells and T cells trigger cellular immunity and destroy those cells which have spike proteins. Now, the body is immune to coronavirus and even if a patient catches the virus and gets infected, his body detects and kills the virus.
EFFICACY:
Research states that the AstraZeneca vaccine is 79 percent effective at Covid-19 protection. Two doses are administrated in the person with an interval of four to six weeks. Some studies suggest that immune response is stronger if the interval period is larger and it provides protection up to 80 percent.
This vaccine has been proven effective against the first strain of Covid-19. Then new strains developed that were stronger and more transmissible.
A study reported that the vaccine is as effective for the UK strain B.1.1.7 and its efficacy is up to 80 percent. While the strain B.1.351 that was detected in South Africa was less protected by this vaccine and efficacy was up to 25 percent. This vaccine could not protect against that mild and moderate infection by this South African variant. But still, the vaccine was able to protect from severe infection.
BENEFITS AND RISKS:
The positive side of the AstraZeneca vaccine is that it is cheaper and can be stored in the fridge, unlike other vaccines. It is effective against most strains of coronavirus. It does not have any direct or indirect effects on pregnancy, breastfeeding and fertility.
The negative side of the vaccine is that it caused thromboembolic effects that caused blood clots. But positive factors of this vaccine overpowers the blood clots that are also rare in study trials. The Covid-19 disease also causes clotting of blood and a decrease in the number of platelets.
Studies suggest that blood clotting and a lower number of platelets is more common in Covid-19 patients rather than in vaccinated people.
Write-up by Muhammad Khurram, Mehreen Fatima
