Adverse Reactions Following Vaccination and Reporting Vaccine Adverse Events

Adverse Reactions Following Vaccination and Reporting Vaccine Adverse Events

Vaccines are intended to produce active immunity to specific antigens. An adverse reaction is an untoward effect caused by a vaccine that is extraneous to the vaccine’s primary purpose of producing immunity. Adverse reactions are also called vaccine side effects. A vaccine adverse event refers to any medical event that occurs following vaccination. An adverse event could be a true adverse reaction or just a coin­cidental event, with further research needed to distinguish between them.

Acute vaccine adverse reactions fall into three general categories: local, systemic, and allergic. The most common type of adverse reactions are local reactions, such as pain, swelling, and redness at the site of injection. Local reactions may occur with up to 80% of vaccine doses, depending on the type of vaccine. Local adverse reactions generally occur within a few hours of the injection and are usually mild and self-limited. On rare occasions, local reactions may be very exaggerated or severe.

Some of these reactions, referred to as Arthus reactions, are most frequently seen with diphtheria and tetanus toxoids. Arthus reactions are not allergic reactions. Arthus reactions are believed to be due to very high titers of antibody, usually caused by too many doses of toxoid.

Systemic adverse reactions are more generalized events and include fever, malaise, myalgias (muscle pain), headache, loss of appetite, and others. These symptoms are nonspecific; they may occur in vaccinated persons because of the vaccine or may be caused by something unrelated to the vaccine.
Systemic adverse reactions were relatively frequent with DTP vaccine, which contained a whole-cell pertussis component. However, comparison of the frequency of systemic adverse events among vaccine and placebo recipients shows they are less common with inactivated vaccines currently in use, including acellular pertussis vaccine.

Systemic adverse reactions may occur following receipt of live attenuated vaccines. Live attenuated vaccines must replicate in order to produce immunity. The adverse reactions that follow live attenuated vaccines, such as fever or rash, represent symptoms produced from viral replication and are similar to a mild form of the natural disease. Systemic adverse reactions following live vaccines are usually mild, and occur 3–21 days after the vaccine was given (i.e., after an incubation period of the vaccine virus). LAIV replicates in the mucous membranes of the nose and throat, not in the lungs. As a result, LAIV may cause upper respiratory symptoms (like a cold) but not influenza-like symptoms.

A third type of acute vaccine adverse reactions are allergic reactions. Allergic reactions may be caused by the vaccine antigen itself or some other component of the vaccine, such as cell culture material, stabilizer, preservative, or antibiotic used to inhibit bacterial growth. Severe allergic reactions (anaphylaxis) may be life-threatening. Fortunately, they are rare. The risk of an allergic reaction can be decreased by good screening prior to vaccination. All providers who administer vaccines must have an emergency protocol and supplies to treat anaphylaxis.

Reporting Vaccine Adverse Events

Providers should report any clinically significant adverse event that occurs after the administration of any vaccine licensed in the United States to the Vaccine Adverse Event Reporting System (VAERS), which includes reporting from both public and private sectors. Providers should report a clinically significant adverse event even if they are unsure whether a vaccine caused the event. The telephone number to call for answers to questions and to obtain VAERS forms is (800) 822-7967, or visit the VAERS website at http://vaers.hhs.gov. VAERS accepts reports of adverse reactions through their online system.

Adverse Reactions Following Vaccination and Reporting Vaccine Adverse Events 2019-01-06T07:10:00-08:00 Rating: 4.5 Diposkan Oleh: David Maharoni