[Show abstract][Hide abstract] ABSTRACT: High attack rates among vaccinated young adults reported during the 2006 mumps outbreak in the United States heightened concerns regarding mumps vaccine failure.
Serum specimens from university students and staff were tested for mumps immunoglobulin (Ig) G by enzyme immunoassay (EIA). A subset of participants vaccinated for < or =5 years and > or =15 years were tested by neutralizing antibody (NA) assay. Persons seronegative by EIA were offered a third dose of measles-mumps-rubella vaccine (MMR3), and serum specimens were obtained 7-10 days and 2-3 months after its administration.
Overall, 94% (95% confidence interval [CI], 91%-96%) of the 440 participants were seropositive. No differences existed in seropositivity rates by sex, age, age at receipt of the second dose of MMR vaccine (MMR2), or time since receipt of MMR2 (P = .568). The geometric mean titer (GMT) of NA among persons vaccinated with MMR2 during the previous 1-5 years was 97 (95% CI, 64-148), whereas, among those vaccinated > or =15 years before blood collection, the GMT was 58 (95% CI, 44-76) (P = .065). After MMR3, 82% (14/17) and 91% (10/11) seroconverted in 7-10 days and 2-3 months, respectively.
Lower levels of NA observed among persons who received MMR2 > or =15 years ago demonstrates antibody decay over time. MMR3 vaccination of most seronegative persons marked the capacity to mount an anamnestic response.
Full-text · Article · Jun 2008 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Background:
The 2006 large-scale, multistate, US mumps outbreak primarily affected vaccinated young adults and raised concerns about mumps vaccine failure. The objectives of this investigation were to evaluate persistence of mumps antibody among young adults previously vaccinated with 2 doses of MMR (MMR2).
Serum specimens from members in a non affected university in Nebraska were tested for mumps IgG by enzyme immunoassay (EIA). A subset of specimens from participants vaccinated < 5 years and > 15 years was tested by plaque-reduction neutralizing assay (PRN). EIA seronegative individuals were offered a third dose of MMR (MMR3). Serum specimens obtained 7-10 days and 2-3 months following MMR3 were tested for IgG by EIA.
The overall seropositivity rate for mumps IgG by EIA (n=440) was 94% (95% CI 91, 96). There were no differences in seropositivity rates by sex, age, age of receipt of MMR2, or time since receipt of MMR2 (p=0.568, trend test 0.265). The geometric mean neutralizing antibody titer (GMT) (n=91) was 66 (95% CI 52, 85). GMTs among individuals vaccinated with MMR2 in the last 1-5 years was 97 (95% CI 64, 148) vs. 58 (95% CI 44, 76) among those vaccinated > 15 years (p=0.065). Seventy six percent (19/25) and 94% (16/17) of seronegative individuals, respectively, seroconverted at 7-10 days and 2-3 months following MMR3.
Lower PRN antibody titers observed among those vaccinated with MMR2 > 15 years may suggest waning antibody to mumps, but it remains unresolved whether this is related to a decrease in immunity. MMR3 vaccination of seronegatives evidenced secondary immune response in most individuals.