Early loss of measles antibodies after MMR vaccine among HIV-infected adults receiving HAART

Abstract

Objective

: The objective of the study was to evaluate the immune response to measles vaccine of HIV-infected adults in comparison to HIV non-infected adults.

Design

We conducted a cross-sectional study to identify adults lacking measles antibodies. 26 HIV-infected patients and 22 controls found to be measles seronegative in the cross-sectional study, received the MMR vaccine. We prospectively followed patients and measured measles antibodies, and cellular proliferative responses against measles antigens. We registered all adverse events at baseline, 3 and 12 months after vaccination.

Methods

We determined measles antibodies by ELISA and cellular proliferative response in PBMC's at baseline, and repeated measurements at 3 and 12 months after vaccination.

Results

The humoral immune response to the vaccine between HIV-infected adults and the HIV-uninfected group was not statistically different at 3 months (81% vs. 86% respectively). One year after vaccination, a higher proportion of HIV-infected adults had lost measles antibodies in contrast to controls. The cellular response was not statistically different between the groups at baseline, 3 and 12 months after immunization despite the waning of antibodies at 12 months. No severe adverse events were observed. Most patients were receiving HAART and had a mean CD4+ cell count of 496 cells/mL.

Conclusions

The initial humoral immune response to measles vaccine was not different between HIV-infected adults and HIV-uninfected adults. However, HIV-infected adults have a rapid decline of measles antibodies despite their high CD4+ cell count and sustained cellular proliferative response.

Introduction

HIV-infected adults may receive the measles vaccine either as part of travel-related immunization [1], or during supplementary immunization activities (SIA) routinely or during ongoing outbreaks [2], [3]. The latter are generally offered through massive immunization campaigns [2], [4], [5], [6], [7]. However, little is known about the safety and efficacy of this vaccine in HIV-infected adults and the measles immunization recommendations for them are based in extrapolations from available data in children [8], [9].

The application of measles vaccine to asymptomatic HIV-infected children is considered to be safe [2], [10], [11], [12]. The initial humoral immune response it elicits might be similar to that achieved by HIV-uninfected children [10], although seroconversion rates range from 25% to 90% [4], [5], [6], [7], [10], [13], [14], [15], [16]. However, little is known about the long-term persistence of measles antibodies after vaccination of HIV-infected subjects, and most of the previous studies have been conducted in children or in adults not receiving HAART [10], [14], [17].

The long-term evaluation of the immune response to the measles vaccine in HIV-infected subjects could provide an insight of the immune response to the measles vaccine. It could also, bring more information about the long-term preservation of measles antibodies among HIV-infected subjects. Furthermore, measles protective immunity has traditionally been evaluated exclusively in terms of antibody detection, despite data suggesting that cell-mediated immunity is essential in the recovery from measles and for long-term maintenance of immunity [18], [19], [20]. The information regarding the cellular immune response to measles vaccination in HIV-infected children and adults is scarce, and the factors associated with primary vaccine failure in HIV-infected individuals are largely unknown.

We conducted this study aiming to prospectively evaluate the short and long-term humoral and cellular immune response to measles vaccine among a group of HIV-infected and non-infected adults. Other objectives of our study were to estimate measles seroprevalence among adults in Mexico and asses the tolerability of measles vaccine among HIV-infected subjects.