COVID-19 vaccine

From Wikipedia, the free encyclopedia August 7, 2021

 

Side effects

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Serious adverse events associated with receipt of new vaccines targeting COVID-19 are of high interest to the public.^[635] All vaccines that are administered via intramuscular injection, including COVID-19 vaccines, have side effects related to the mild trauma associated with the procedure and introduction of a foreign substance into the body.^[636] These include soreness, redness, rash, and inflammation at the injection site. Other common side effects include fatigue, headache, myalgia (muscle pain), and arthralgia (joint pain) which generally resolve within a few days.^[637] One less-frequent side effect (that generally occurs in less than 1 in 1,000 people) is hypersensitivity (allergy) to one or more of the vaccine's ingredients, which in some rare cases may cause anaphylaxis.^{[638][639][640][641]}

 

Specific rare side effects

More serious side effects are very rare because a vaccine would not be approved even for emergency use if it had any known frequent serious adverse effects.

For example, the Janssen COVID-19 vaccine reported rare Formation of blood clots in the blood vessels in combination with low levels of blood platelets known as thrombosis with thrombocytopenia syndrome (TTS) which occurred at a rate of about 7 per 1 million vaccinated women ages 18–49 years old; and even more rarely for other populations.^[642] 

According to the CDC, very rare cases of myocarditis and pericarditis have been reported in the United States, in about 13 per million young people (mostly in males and mostly over the age of 16), after vaccination with the Pfizer–BioNTech's or Moderna's vaccines.^[643] According to reports, the recovery from these rare side effects is quick in most individuals, following adequate treatment and rest.^[644]

5Trial and authorization status

5.1List of authorized and approved vaccines

5.2Vaccine candidates in human trials

5.2.1Homologous prime-boost vaccination

5.2.2Heterologous prime-boost vaccination

Trial and authorization status

Phase I trials test primarily for safety and preliminary dosing in a few dozen healthy subjects, while Phase II trials – following success in Phase I – evaluate immunogenicity, dose levels (efficacy based on biomarkers) and adverse effects of the candidate vaccine, typically in hundreds of people.^[95][96] A Phase I–II trial consists of preliminary safety and immunogenicity testing, is typically randomized, placebo-controlled, while determining more precise, effective doses.^[96] Phase III trials typically involve more participants at multiple sites, include a control group, and test effectiveness of the vaccine to prevent the disease (an "interventional" or "pivotal" trial), while monitoring for adverse effects at the optimal dose.^[95][96] Definition of vaccine safety, efficacy, and clinical endpoints in a Phase III trial may vary between the trials of different companies, such as defining the degree of side effects, infection or amount of transmission, and whether the vaccine prevents moderate or severe COVID‑19 infection.^{[97][147][148]}

A clinical trial design in progress may be modified as an "adaptive design" if accumulating data in the trial provide early insights about positive or negative efficacy of the treatment.^[149][150] Adaptive designs within ongoing Phase II–III clinical trials on candidate vaccines may shorten trial durations and use fewer subjects, possibly expediting decisions for early termination or success, avoiding duplication of research efforts, and enhancing coordination of design changes for the Solidarity trial across its international locations.^[149][151]

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Unsolicited Adverse Events

Reports of lymphadenopathy were imbalanced with 58 more cases in the vaccine group (64) than the placebo group (6); lymphadenopathy is plausibly related to the vaccine. Lymphadenopathy occurred in the arm and neck region and was reported within 2 to 4 days after vaccination. The average duration of lymphadenopathy was approximately 10 days. Bell’s palsy was reported by four vaccine recipients and none of the placebo recipients. The observed frequency of reported Bell’s palsy in the vaccine group is consistent with the background rate in the general population, and there is no basis upon which to conclude a causal relationship.   https://www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/reactogenicity.html

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Serious Adverse Events--Over 18 of age

Serious adverse events were defined as any untoward medical occurrence that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, or resulted in persistent disability/incapacity. The proportions of participants who reported at least 1 serious adverse event were 0.6% in the vaccine group and 0.5% in the placebo group. The most common serious adverse events in the vaccine group which were numerically higher than in the placebo group were appendicitis (7 in vaccine vs 2 in placebo), acute myocardial infarction (3 vs 0), and cerebrovascular accident (3 vs 1). Cardiovascular serious adverse events were balanced between vaccine and placebo groups. Two serious adverse events were considered by U.S. Food and Drug Administration (FDA) as possibly related to vaccine: shoulder injury possibly related to vaccine administration or to the vaccine itself, and lymphadenopathy involving the axilla contralateral to the vaccine injection site. Otherwise, occurrence of severe adverse events involving system organ classes and specific preferred terms were balanced between vaccine and placebo groups.