In a period of just over three weeks, over four million people received Moderna’s COVID-19 vaccine. Out of all these people, only 10 developed a severe allergic reaction, says a report released by the Centers for Disease Control and Prevention (CDC).
At 2.5 adverse events for every 1 million individuals vaccinated, this data points to the vaccine being safe for the general population. "Based on this early monitoring, anaphylaxis after receipt of Moderna COVID-19 vaccine appears to be a rare event," say authors of the CDC report.
For those that did develop adverse symptoms to the treatment, it appears that having allergies to other medications including penicillin may be a risk factor. One individual was known to be allergic to some foods and environmental factors but had no known drug sensitivities. Further investigations are underway to understand the mechanism behind the response to the vaccine.
The report states that all 10 patients received a range of treatments to alleviate the allergic symptoms, from epinephrine shots to emergency hospitalization, but all were reported to have recovered.
The main ingredient of the vaccine in mRNA encoding the viral spike protein. Once synthesized by cells, the body begins to make protective antibodies against the foreign protein, helping to shield against future infections should the individual come into contact with the SARS-CoV-2 virus. Half a milliliter of the vaccine solution is injected into the arm and for best results, individuals need to get two doses, a month apart. Previous studies found the Moderna vaccine to be 94.1 percent effective in preventing COVID infections after both doses.
According to allergy expert at NYU Langone Health, Purvi Parikh, true allergic reactions to vaccines are exceedingly rare. "Statistically, you're more likely to be hit by lightning than have a true anaphylactic reaction to a vaccine," said Parikh.
As scientists continue to determine what ingredient in the vaccine is causing these rare anaphylactic events, their message to the community is not to get dissuaded from getting the vaccine.