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Why is anaphylaxis, fatal after vaccination with Covid-19? – VnExpress


Cases of anaphylactic shock and death following Covid-19 vaccination have caused many people to worry, questioning why and whether the vaccine is affected.

Like all new drugs, vaccines, once licensed, can still cause side effects. Many people, after getting vaccinated by Pfizer-BioNTech or Moderna, experienced symptoms such as fever, headache, fatigue, and numbness at the injection site.

Most of these side effects go away quickly. Others experience anaphylaxis, but can be cured. However, to a greater degree, Norway has reported deaths following the Pfizer vaccination in frail elderly, with underlying disease.

Dead

29 of the 42,000 people vaccinated with the Pfizer-BioNTech vaccine have died in Norway, a country that prioritizes vaccinations for nursing home residents. Each case is being investigated for clarification. But the authorities said there was no evidence to suggest a direct link between the vaccine and the deaths.

The dead were over 75 years old, most of them very old and frail and seriously ill. In addition, an average of 400 people die each week in nursing homes, according to the Norwegian Pharmaceutical Authority. The agency’s chief physician, Sigurd Hortemo thinks that common side effects such as fever or nausea can progress in a serious, life-threatening course for a person with a serious illness.

A resident is vaccinated with Covid-19 vaccine in Boston, USA, December 2020. Image:AFP

In Germany, more than 800,000 people received the first dose of the Pfizer-BioNTech vaccine. A report by the Paul Ehrlich Research Institute found that 10 elderly people died shortly after Covid-19 vaccination. The cause of death can be due to underlying diseases including carcinoma, kidney failure and Alzheimer’s, not from vaccines.

Deaths in Norway associated with short-term symptoms such as fever, nausea, and diarrhea are common among vaccinated people, according to Therapeutics Australia, which works with the Drug Administration. European products including Norway. On the other hand, millions of doses of Pfizer-BioNTech vaccine have been used in the US, UK and many other countries but no deaths have occurred, according to Abrar Chughtai, a lecturer at the School of Public Health and Community Medicine, of the University of New South Wales.

According to medical experts, these risks are not many. Steinar Madsen, medical director of the Norwegian Drug Agency, said that the side effects are not dangerous in younger people, but may worsen the underlying condition in the elderly. In the trial prior to the provisional licensing of the Pfizer-BioNTech vaccine in Norway, the number of people over 85 years old was limited. The majority of participants are in their 50s.

The Norwegian Institute of Public Health has updated more detailed instructions on what to note when giving Covid-19 vaccination to the elderly. “We are asking doctors to check and evaluate the status of people who are sick before starting the vaccination,” Mr. Madsen said.

The assessment process involves communicating with patients and family members about the vaccine benefits and risks. In addition, Norway recommends not vaccinating people with terminal illnesses receiving palliative care, as side effects such as fever can weaken the patient.

Anaphylaxis

The body fights off the virus by producing antibodies, releasing toxins, and mobilizing protective cells to deal with the “intruder”. A war can have more or less damage. In some cases, the process can cause anaphylaxis, leading to inflammation and swelling of the tissues.

About 5% of the US population reacts like this to different substances. Although very rare, anaphylaxis can be fatal if the airways are blocked. This phenomenon occurs when a person is allergic to food, insect stings. Drug reactions are the most common cause of death from anaphylaxis in the US and UK.

According to a report on Jan. 6 by the US Centers for Disease Control and Prevention (CDC), 29 cases of anaphylactic shock related to vaccines Pfizer-BioNTech and Moderna were confirmed in the country from 14 to 23 / 12/2020. Among them, 17 had a history of allergy and 7 had a history of anaphylaxis. He recorded 2 cases, and in Israel – a man in anaphylactic shock an hour after the injection. This person said he was allergic to penicillin. The CDC says it has been reported on the side effects of the Moderna vaccine and is synthesizing the information.

This dangerous reaction occurs only about 1.3 times per million doses of the flu vaccine used. With other vaccines, the number falls between 12 and 25 times per million. For the Pfizer-BioNTech Covid-19 vaccine, according to the CDC, the rate was 11.1 per million as of December 23, 2020. The risk surrounding the vaccine is much smaller than the risk of a serious complication from Covid-19, the agency said.

Michael Kinch, a pharmacy expert and vice president at the University of Washington, said anaphylaxis usually occurs within minutes to hours after exposure to a particular substance. So far, symptom onset time in the US has ranged from 2 to 150 minutes, with an average of 13 minutes, according to the CDC.

The UK and US recommend that people allergic to any of the ingredients of the Covid-19 vaccine should not be vaccinated. Anaphylaxis can be resolved quickly with an antihistamine coupled with adrenaline that slows or suppresses immune responses. The medical staff in charge of the vaccination should have these medications available.

The treatments listed above do not counteract the beneficial effects of the vaccine. In the US, all citizens are monitored for at least 15 minutes after an injection. People with a history of drug allergy were followed for twice as long. Individuals who develop a reaction on the first Covid-19 vaccination should not get a second shot.

Mai Dung (According to the Bloomberg)

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