Vaccine Shedding
Vaccine shedding is typically described as the excretion of the vaccine strain virus after the administration from a live virus vaccine.
​
Cases:
MMR:
Multiple cases listed under "Outbreaks and Shedding" on MMR Controversies page > for quick navigation click button below
Also stated in the MMR insert on page 5
"Excretion of small amounts of the live attenuated rubella virus from the nose or throat has occurred in the majority of susceptible individuals 7 to 28 days after vaccination"
Varicella:
" A 12 month old healthy boy had approximately 30 vesicular skin lesions 24 days after receiving varicella vaccine. Sixteen days later his pregnant mother had 100 lesions. "
a 38-year-old healthy white woman developed a rash consisting of 30 scattered lesions. Sixteen days
later, her 2 children also developed rash."
"Five months after 2 siblings were immunized with varicella vaccine, 1 developed zoster. Two weeks later the second sibling got a mild case of chicken pox. Virus isolated from the latter was found to be vaccine type. Thus, the vaccine strain was transmitted from the vaccinee with zoster to his sibling. Vaccinees who later develop zoster must be considered contagious"
Rotavirus:
"We document here the occurrence of vaccine-derived rotavirus (RotaTeq [Merck and Co, Whitehouse Station, NJ]) transmission from a vaccinated infant to an older, unvaccinated sibling, resulting in symptomatic rotavirus gastroenteritis that required emergency department care."
Page 4:
"In phase 3 studies, shedding was observed as early as 1 day and as late as 15 days after a dose. Transmission of vaccine virus was not evaluated in phase 3 studies.
​
Transmission of vaccine virus strains from vaccinees to non-vaccinated contacts has been observed post-marketing."
DTaP:
FDA Scientists conducted a study on the acellular pertussis vaccine by infecting baboons with the virus.
​
None of the vaccinated or naturally immune baboons became ill with pertussis. However the virus lingered in the throats of the baboons that were vaccinated for 35 days. The baboons that were vaccinated with the acellular pertussis vaccine were able to pass the infection onto other baboons.