Multiple studies have found no causal link between Moderna’s mRNA COVID-19 vaccines and blood clots or any change of shapes in red blood cells.
According to Nature, blood clots due to vaccinations are uncommon in young people, and it's even rarer to see a combination of blood clots and dangerously low levels of platelets cell fragments that help form clots. Some researchers believe that leftover impurities from the manufacturing process, such as snippets of DNA floating around in the solution or proteins in the virus-growing broth, interact with platelet factor 4 (PF4) to form antibodies then target the clumps.
Moderna listed some side effects of the vaccines like pain at the injection site, fatigue, headache, chills, nausea, vomiting, fever, myocarditis, and pericarditis. So far, there is no link to the blood clots.
On December 18, 2020, the Food and Drug Administration (FDA) had issued an Emergency Use Authorization (EUA) to Moderna COVID-19 vaccine for active immunization to prevent COVID-19 in individuals 18 years of age and older. Moderna uses the same mRNA technology as Pfizer and has a high efficacy at preventing symptomatic disease. Even the clinical trials involving tens of thousands of people revealed that the vaccine was safe and effectively prevented coronavirus infection. It found no link between vaccines and autoimmune diseases.
Moderna's initial Phase 3 clinical data in December 2020 was similar to Pfizer's - at that point, both vaccines showed about 95 percent efficacy. According to its press release, six months after vaccination, the Moderna vaccine was shown to have an effectiveness of 90 percent against infection and more than 95 percent against developing a severe case.
Centers for Disease Control and Prevention (CDC) and European Medicines Agency closely monitor any potential side effects of the vaccines approved for emergency use against COVID-19.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19, including symptoms, prevention, and available treatment, please refer to the World Health Organization or your national healthcare authority.