U.S. FDA to inspect COVID-19 vaccine designs linked to blood clots

U.S. government scientists are reportedly inspecting two COVID-19 vaccines for possibly rare blood clotting scenarios identified in brains. These scientists are focusing on whether a specific technology used for producing these shots may be causing these blood clots.

Health regulators in Europe apparently stated that there is a possible connection between the AstraZeneca Plc vaccine and over 169 cases of a particular blood clot, called cerebral venous sinus thrombosis, along with low count of blood platelets. The regulators observed these cases out of nearly 34 million vaccine shots from the European region.

U.S. FDA recently recommended a temporary halt of the distribution of the Johnson & Johnson vaccine, after six cases of cerebral venous sinus thrombosis came to light, especially in women under the age of 50 amongst the seven million people who received the vaccines in U.S.

The AstraZeneca vaccine and the Johnson & Johnson vaccines are based on adenovirus, which generally causes common cold. These viruses have been modified to make them harmless. The viruses are used as vectors to transmit instructions for human cells to create proteins found on the surface of the SARS-COV-2 virus, thus prompting the immune system to produce antibodies that can fight the actual virus.

Scientists are currently working on identifying the mechanism that can possibly explain the blood clots.

FDA officials have apparently stated that a leading  theory suggests that the vaccine shots are triggering a rare response from the immune system that could be connected to these viral vectors.

Using these viral vectors, the U.S. agency will examine data acquired from the clinical trials of multiple vaccines, which includes the Ebola vaccine of Johnson & Johnson.

Previously, no vaccines using viral vectors have been administered to the scale of J&J and the AstraZeneca COVID-19 vaccines. This could explain why a possible link to blood clots only came up during the large-scales administration of these vaccination programs.

Source Credits:

https://www.reuters.com/article/us-health-coronavirus-johnson-johnson-in/u-s-fda-to-scrutinize-vaccine-design-behind-covid-19-shots-linked-to-blood-clots-idUSKBN2C02UI