Breakthrough infection
Encyclopedia
A breakthrough infection is an infection
caused by the live virus
in a vaccine
or, simply, a vaccinated individual becoming sick with the same illness that the vaccine is meant to prevent. Often, the infection in the vaccinated individual is milder than if contracted naturally. A breakthrough infection can be especially dangerous in locations where herd immunity
exists.
There are many theories which attempt to explain the causes of breakthrough infections such as antibody
interference or vaccine compromise due to mishandling.
There is some evidence that breakthrough measles occurring in a vaccinated patient is less serious than the same measles infection in an unvaccinated patient.
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
caused by the live virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
in a vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
or, simply, a vaccinated individual becoming sick with the same illness that the vaccine is meant to prevent. Often, the infection in the vaccinated individual is milder than if contracted naturally. A breakthrough infection can be especially dangerous in locations where herd immunity
Herd immunity
Herd immunity describes a form of immunity that occurs when the vaccination of a significant portion of a population provides a measure of protection for individuals who have not developed immunity...
exists.
There are many theories which attempt to explain the causes of breakthrough infections such as antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
interference or vaccine compromise due to mishandling.
There is some evidence that breakthrough measles occurring in a vaccinated patient is less serious than the same measles infection in an unvaccinated patient.