Asthma Status and Waning of Measles Immunization
Background: Asthmatics have increased risks of common and serious microbial infections including vaccine preventable diseases. Little is known about whether asthma influences waning of humoral immunity. We assessed whether asthma status influences waning of anti-measles virus antibody concentrations over time.
Methods: The study used a cross-sectional study cohort of healthy children who had been immunized with 1 dose of MMR-II at age approximately 15 months. Between 5 and 12 years of age, measles vaccine virus-specific antibody (IgG) values were measured by enzyme immunoassay and considered seropositive if the enzyme immunoassay index unit was ≥ 1. The medical records were reviewed to determine asthma status during the first 18 years of life by applying predetermined criteria for asthma. A least squares regression model was used to evaluate the effect of asthma status on the relationship between measles antibody titer and time elapsed between the initial measles vaccination and measurement of measles antibody concentrations.
Results: Of the 838 eligible children, 281 (34%) met criteria for asthma. Measles antibody waned over time (r = −0.19, P < 0.001), specifically more rapidly in asthmatics (r = −0.30, P < 0.001, a decrease of −0.114 unit per year) than non-asthmatics (r = −0.13, P = 0.002, a decrease of −0.046 unit per year; P value for interaction = 0.010). This differential waning rate resulted in a lower mean (SD) measles antibody concentration [1.42 (0.67) vs. 1.67 (0.69), P = 0.008] and lower seropositivity rate (73% vs. 84%, P = 0.038) in asthmatics than non-asthmatics starting around 9.3 years after the initial measles vaccination.
Conclusion: Asthma status is associated with waning kinetics of measles antibody among children.
In 2010, there were 139,000 deaths because of measles globally. Despite the effectiveness of the vaccine, measles outbreaks continue to occur throughout the world. There were 222 measles cases in the United States reported from 31 states in 2011 and more than 30,567 measles cases reported in the WHO European Region. Five European countries (France, Italy, German, Spain and Romania) accounted for 90% of these cases.
Despite the reported long-lasting humoral immunity against measles (25 years to life long), there are some concerns about waning or decay of measles vaccine-induced humoral immunity in terms of the potential for reemergence of measles in developed countries and the possible impediment to the eradication of measles. A few studies have predicted the difficulty of sustaining complete elimination of measles because of waning of immunity based on mathematical models (or even primary vaccine failure). Research efforts concerning identification of factors potentially associated with waning of measles vaccine virus-specific antibody are limited. A few previous studies have reported general subject characteristics (sociodemographic or serologic features) in relation to waning of measles antibody. To date, no study has been conducted to assess the impact of prevalent immune-mediated chronic conditions such as asthma on waning of measles vaccine virus-specific antibody. This concern becomes especially relevant considering that asthma has been reported to be associated with an increased risk of microbial infections and suboptimal innate and adaptive immune functions. Also, a few recent papers demonstrated evidence of waning of pertussis, mumps and measles vaccine-induced immunity in children and its potential impact on public health. Despite the public health concerns over the outbreaks of vaccine preventable diseases in the United States and elsewhere, currently there are scant data about factors influencing waning of vaccine-induced humoral immunity.
We explored whether asthma status affects waning of adaptive immunity and hypothesized that asthmatics have a more rapid waning of measles antibody than non-asthmatics. To test this hypothesis, we compared waning of measles antibody between children with and without a history of asthma using subjects from a previous cross-sectional community vaccine study.
Abstract and Introduction
Abstract
Background: Asthmatics have increased risks of common and serious microbial infections including vaccine preventable diseases. Little is known about whether asthma influences waning of humoral immunity. We assessed whether asthma status influences waning of anti-measles virus antibody concentrations over time.
Methods: The study used a cross-sectional study cohort of healthy children who had been immunized with 1 dose of MMR-II at age approximately 15 months. Between 5 and 12 years of age, measles vaccine virus-specific antibody (IgG) values were measured by enzyme immunoassay and considered seropositive if the enzyme immunoassay index unit was ≥ 1. The medical records were reviewed to determine asthma status during the first 18 years of life by applying predetermined criteria for asthma. A least squares regression model was used to evaluate the effect of asthma status on the relationship between measles antibody titer and time elapsed between the initial measles vaccination and measurement of measles antibody concentrations.
Results: Of the 838 eligible children, 281 (34%) met criteria for asthma. Measles antibody waned over time (r = −0.19, P < 0.001), specifically more rapidly in asthmatics (r = −0.30, P < 0.001, a decrease of −0.114 unit per year) than non-asthmatics (r = −0.13, P = 0.002, a decrease of −0.046 unit per year; P value for interaction = 0.010). This differential waning rate resulted in a lower mean (SD) measles antibody concentration [1.42 (0.67) vs. 1.67 (0.69), P = 0.008] and lower seropositivity rate (73% vs. 84%, P = 0.038) in asthmatics than non-asthmatics starting around 9.3 years after the initial measles vaccination.
Conclusion: Asthma status is associated with waning kinetics of measles antibody among children.
Introduction
In 2010, there were 139,000 deaths because of measles globally. Despite the effectiveness of the vaccine, measles outbreaks continue to occur throughout the world. There were 222 measles cases in the United States reported from 31 states in 2011 and more than 30,567 measles cases reported in the WHO European Region. Five European countries (France, Italy, German, Spain and Romania) accounted for 90% of these cases.
Despite the reported long-lasting humoral immunity against measles (25 years to life long), there are some concerns about waning or decay of measles vaccine-induced humoral immunity in terms of the potential for reemergence of measles in developed countries and the possible impediment to the eradication of measles. A few studies have predicted the difficulty of sustaining complete elimination of measles because of waning of immunity based on mathematical models (or even primary vaccine failure). Research efforts concerning identification of factors potentially associated with waning of measles vaccine virus-specific antibody are limited. A few previous studies have reported general subject characteristics (sociodemographic or serologic features) in relation to waning of measles antibody. To date, no study has been conducted to assess the impact of prevalent immune-mediated chronic conditions such as asthma on waning of measles vaccine virus-specific antibody. This concern becomes especially relevant considering that asthma has been reported to be associated with an increased risk of microbial infections and suboptimal innate and adaptive immune functions. Also, a few recent papers demonstrated evidence of waning of pertussis, mumps and measles vaccine-induced immunity in children and its potential impact on public health. Despite the public health concerns over the outbreaks of vaccine preventable diseases in the United States and elsewhere, currently there are scant data about factors influencing waning of vaccine-induced humoral immunity.
We explored whether asthma status affects waning of adaptive immunity and hypothesized that asthmatics have a more rapid waning of measles antibody than non-asthmatics. To test this hypothesis, we compared waning of measles antibody between children with and without a history of asthma using subjects from a previous cross-sectional community vaccine study.