Photographer: Eva Marie Uzcategui / Bloomberg
Photographer: Eva Marie Uzcategui / Bloomberg
As with all new medicines, the Covid-19 vaccines approved in Western countries have safety and side effects. Many people who received the first two shots, one of Pfizer Inc. and BioNTech SE and another of Moderna Inc., experienced fever, headache, and pain at the injection site. These side effects generally go away quickly. As many as ten people had a severe allergic reaction to the vaccines, called anaphylaxis.
1. What is anaphylaxis?
The body fights foreign invaders through a variety of mechanisms that include making protective proteins called antibodies, releasing toxins that kill microbes, and protective cells to fight the infection. As in any conflict, trying to ward off an infection can sometimes be harmful. In rare cases, it can cause noticeable inflammation and swelling of tissues in a severe allergic reaction anaphylaxis. As much as 5% of people in the US reacted this way to different substances. It can be fatal if the person’s airway swells, for example, although deaths are Rare. Allergies to insect stings and food can provoke it, although drug reactions most common cause of anaphylaxis deaths in US and UK
2. Where did Covid vaccines cause cases?
A December 19 presentation from the U.S. Centers for Disease Control and Prevention refers to two cases of anaphylaxis associated with the Pfizer-BioNTech vaccine in the UK and six in the US. A health care worker in Alaska who received a shot had to be admitted to the hospital overnight. Later that month, in Israel, using the Pfizer BioNTech vaccine, a man suffered an anaphylactic shock an hour after receiving a shot. according to the Jerusalem Post. He said he had had reactions to penicillin earlier, the newspaper reported. And a doctor in Boston with a shellfish allergy reported that he had a anaphylactic reaction to Moderna’s vaccine. None of the reactions resulted in death.
3. Have anaphylaxis been linked to vaccines before?
Yes. ‘N 2016 study in the Journal of Allergy and Clinical Immunology found 33 cases of vaccine-induced anaphylaxis occur after 25,173,965 doses of vaccinations, a dose of about 1.31 per million doses. So far, the rate for known cases related to the administration of approx. 3 million doses of Pfizer and Moderna vaccines appear to be more than double, but still very low.
4. How long does the risk last?
Usually not for long. Anaphylactic reactions usually occur within minutes to hours after exposure to a specific substance, said Michael Kinch, an expert in medicine development and co-vice chancellor at Washington University in St. Of the 29 cases where the delay was documented in the 2016 study, symptoms of anaphylaxis started in eight cases within 30 minutes, within the next 90 minutes in another eight, within two to four hours in 10 cases, within four to eight hours in two cases, and the next day in one.
5. What is being done about the risk?
The United Kingdom and the US has advised people who are allergic to any component of a Covid vaccine not to receive it. Anaphylaxis can be quickly combated with antihistamines and adrenaline injectors such as Mylan NV’s Epi-Pen which slows or stops immune responses, and healthcare professionals who give the vaccine keep such items ready. These treatments do not cancel out the beneficial effects of vaccines. In the US, health workers observe someone who has received the vaccine for at least 15 minutes after the injection to notice signs of reaction. People who have had reactions to a first dose of vaccine should, according to the CDC.
6. Do we know what causes the reactions?
It is not clear. The two leading candidates are polyethylene glycol – a chemical found in many foods, cosmetics and medicines – and lipid nanoparticles encapsulating the messenger RNA, a genetic component in vaccines, according to Eric Topol, a clinical expert and director of the Scripps Translational Institute. Polyethylene Glycol is previously linked to a handful of anaphylactic cases. Once a cause has been narrowed down, it is possible to make Covid vaccines even safer than now, Topol said. When other serious non-allergic side effects pop up, he said, “it’s probably pretty rare and the net benefit of vaccination is overwhelmingly positive.”