Secondary immune response in a vaccinated population during a large measles epidemic

Abstract

The rates of secondary immune response (SIR) and secondary vaccine failure (SYF) during a measles epidemic (10,184 notifications) were evaluated. A patient with SIR was defined as a subject for whom all sera were immunoglobulin G (IgG) positive and IgM negative with a significant increase in complement fixation titer. A patient with SVF was defined as a vaccinated symptomatic subject showing a SIR. Sequential sera from 898 subjects were tested for measles antibody by enzyme-linked immunosorbent assay (IgG and IgM) and by complement fixation. Evidence of recent anti-measles virus specific immune response was found in 496 subjects (55.5%). The vaccination rate was estimated at 74.6% (99% confidence interval [CI], 67.9 to 80.7%). The number of exposed vaccinated subjects was estimated at 370 (74.6% of 496). The SIR rate was 4.03% (20 of 496) (99%v CI, 2.1 to 6.9%o) among subjects with immune response. These 20 subjects were 2 with measles (Centers for Disease Control's definition), 6 with measles with rash of unknown duration, 8 with presumed measles with either rash or fever, 3 asymptomatic subjects (2 with recent contact with a measles case), and 1 undocumented subject. Since 3 patients with SIR were asymptomatic and 2 others were documented as not vaccinated, there was a maximum of 15 probable occurrences of SVF among the 20 patients with SIR. The SVF rate among exposed vaccinated subjects was estimated at 4.05% (15 of 370) (99% CI, 1.9 to 7.5%). In conclusion, neither prior vaccination nor detectable SIR ensures protective immunity. Measles virus may induce asymptomatic SIR in IgG-seropositive subjects. SVF led to typical or modified measles but did not seem to have played an important role during this epidemic.

Characteristics of asymptomatic secondary immune responses to measles virus in late convalescent donors

“…Seronegative people generally develop clinical measles. While seropositivity normally protects against disease, this study confirms that a SIR occurs in at least some protected individuals [12]. Among 44 fully protected, measles late convalescent parents reexposed to measles, four developed an asymptomatic SIR with a significant increase in MV-specific IgG.…”

“…In this context, the transient nature of the SIR seems to indicate that such individuals can be efficiently protected from disease, but not from infection. The frequency of SIR during measles outbreak was about 5% [12,20], but the number of susceptibles to SIR may be considerably higher. Our data can be used to estimate the frequency of susceptibles on the basis of their pre-existing IgG, NT and HI levels.…”

Systematic Review of Measles and Rubella Serology Studies

“…We identified over 220 studies that provided cross‐sectional data and nearly 180 studies that reported on immunity for women of child‐bearing age, primarily for rubella. Table summarizes the over 400 cross‐sectional and women of child‐bearing age measles and rubella serological studies…”

Estimated susceptibility to asymptomatic secondary immune response against measles in late convalescent and vaccinated persons

“…Symptomatic secondary immune response is mainly seen as secondary vaccine failure and is only rarely found in measles convalescents [Aaby et al, 1986;Edmonson et al, 1990;Miller et al, 1995]. Most estimates of secondary vaccine failure range from 0 [Gustafson et al, 1987;Anders et al, 1996] to about 5% of either the measles patients or the vaccinees [Edmonson et al, 1990;Ozanne and d'Halewyn, 1992]. Measurements of Values are given as exponentials and correspond to the data of Figure 2.…”

“…In the absence of seronegative individuals, several observations indicate that measles virus (MV) can circulate also among seropositive persons without signs of clinical measles [Pedersen et al, 1989]. After reexposure to measles, specific IgGpositive subjects may sometimes present with mild disease [Aaby et al, 1986;Edmonson et al, 1990] and protected individuals can develop asymtomatic secondary immune responses [Gustafson et al, 1987;Pedersen et al, 1989;Ozanne and d'Halewyn, 1992]. Subclinical secondary immune response to measles has been observed in immunized populations [Gustafson et al, 1987;Pedersen et al, 1989;Ozanne and d'Halewyn, 1992].…”