Photographer: Eva Marie Uzcategui / Bloomberg
Photographer: Eva Marie Uzcategui / Bloomberg
Like all new drugs, Covid-19 vaccines that have been licensed in Western countries come with some safety issues and side effects. Many people who received the first two photos taken, one of Pfizer Inc. and BioNTech SE and another from Moderna Inc., presented with fever, headache and pain at the injection site. These side effects generally go away quickly. Up to 10 people had a severe allergic reaction, called anaphylaxis, to vaccines.
1. What is anaphylaxis?
The body fights foreign invaders through a variety of mechanisms that include the manufacture of protective proteins called antibodies, the release of toxins that kill microbes, and the organization of guard cells to fight infection. As in any conflict, sometimes the effort to repel an infection can be harmful in itself. In rare cases, it can cause fugitive inflammation and swelling of the tissues in a severe allergic reaction called anaphylaxis. As much as 5% of people in the US had such a reaction to various substances. It can be fatal if, for example, a person’s airways become swollen, even though there are deaths rarely. Allergies to insect bites and food can cause it, although drug reactions are the most common cause of anaphylaxis deaths in the US and the UK
2. Where did the Covid vaccine cases start?
A December 19th The presentation at the US Centers for Disease Control and Prevention referred to two cases of anaphylaxis associated with the Pfizer-BioNTech vaccine in the United Kingdom and six in the United States. Later in the month, in Israel, which carries the Pfizer-BioNTech vaccine, a man suffered anaphylactic shock an hour after receiving a blow, according to the Jerusalem Post. He said he had previous reactions to penicillin, the newspaper said. And a Boston doctor with a shellfish allergy reported having a anaphylactic reaction to the Modern vaccine. None of the reactions led to death.
3. Has anaphylaxis been linked to vaccines?
Yes. A 2016 The study in the Journal of Allergy and Clinical Immunology found 33 confirmed cases of vaccine-triggered anaphylaxis that occurred after 25,173,965 inoculation doses, a rate of about 1.31 to one million doses. To date, the rate for known cases related to administration is approximately 3 million doses of Pfizer and Moderna vaccines seem to be more than double, but still very low.
4. How long does the risk last?
Usually not much. Anaphylactic reactions normally occur within minutes to hours of exposure to a particular substance, said Michael Kinch, a drug development expert and associate chancellor at University of Washington in St. Louis. Of the 29 cases in which the gap was documented in the 2016 study, symptoms of anaphylaxis began in 30 minutes in eight cases, in the next 90 minutes in another eight, in two to four hours in 10 cases, in four to four. at eight o’clock in two cases, and the next day in one.
5. What is done about the risk?
UK and the US have advised people who are allergic to any component of a Covid vaccine not to receive it. Anaphylaxis can be quickly counteracted with antihistamines and adrenaline injectors, such as Epi-Pen from Mylan NV, which slow down or stop immune reactions, and the health workers who administer the vaccine keep such items ready. These treatments do not negate the beneficial effects of vaccines. In the US, health care workers observe anyone who has received the vaccine for at least 15 minutes after the injection to look for signs of a reaction. People who have had reactions to a first dose of vaccine should not get a second one, according to CDC.
6. Do we know what causes the reactions in photos?
It is not clear. The two main candidates are polyethylene glycol – a chemical found in many foods, cosmetics and medicines – and lipid nanoparticles that encapsulate messenger RNA, a genetic component in vaccines, according to Eric Topol, clinical trial expert and director of Scripps Research Translational Institute. Polyethylene glycol was previously linked to a handful of cases of anaphylaxis. Once a cause has been reduced, it is possible to make Covid vaccines even safer than they are now, Topol said. If other serious non-allergic side effects occur, he said, “they are also likely to be quite rare and the net benefit of vaccination is overwhelmingly positive.”