Higher Risk of Measles When the First Dose of a 2-Dose Schedule of Measles Vaccine Is Given at 12-14 Months Versus 15 Months of Age
ABSTRACT In 2011, >750 cases of measles were reported in Quebec, Canada, where a routine 2-dose measles immunization schedule, in which measles vaccine is given at 12 and 18 months of age, had been in effect since 1996. Effectiveness of this schedule was assessed during a high school outbreak.
Cases were identified by passive followed by active surveillance. Classical cases met the national surveillance definition; attenuated cases showed clinical signs and high measles-specific immunoglobulin G but did not fulfill all classical criteria. Immunization status was ascertained from written records, and vaccine effectiveness (VE) was calculated as 1 - [(risk of measles in vaccinated individuals)/(risk in unvaccinated individuals)] × 100%.
Among 1306 students, 110 measles cases were identified; 98 were classical cases, and 12 were attenuated cases. The attack rates among unvaccinated and fully vaccinated students were 82% and 4.8%, respectively. The VE among 2-dose recipients was 95.5% against classical and 94.2% against all (classical + attenuated) measles. Among 2-dose recipients, attack rates with first immunization at 12 and ≥15 months of age were 5.8% and 2.0%, respectively, with corresponding VE values of 93.0% and 97.5%. The risk of measles in 2-dose recipients was significantly (3-4-fold) higher when vaccine was first administered at 12 months of age, compared with ≥15 months of age (P = .04).
Despite compliance with the recommended 2-dose measles immunization schedule, 6% of high school students were susceptible during this outbreak. Residual susceptibility was 2-4-fold higher among 2-dose recipients who had received the first dose of vaccine prior to 15 months of age. If confirmed in other settings, these results suggest that administration of the first dose of measles vaccine before 15 months of age may not be optimal for measles elimination efforts.
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ABSTRACT: Most of the research effort regarding asthma has been devoted to its causes, therapy, and prognosis. There is also evidence that the presence of asthma can influence patients' susceptibility to infections, yet research in this aspect of asthma has been limited. There is additional debate in this field, with current literature tending to view the increased risk of infection among atopic patients as caused by opportunistic infections secondary to airway inflammation, especially in patients with severe atopic diseases. However, other evidence suggests that such risk and its underlying immune dysfunction might be a phenotypic or clinical feature of atopic conditions. This review argues (1) that improved understanding of the effects of asthma or other atopic conditions on the risk of microbial infections will bring important and new perspectives to clinical practice, research, and public health concerning atopic conditions and (2) that research efforts into the causes and effects of asthma must be juxtaposed because they are likely to guide each other.Journal of Allergy and Clinical Immunology 08/2014; 134(2):247–257.e3. DOI:10.1016/j.jaci.2014.04.024 · 11.25 Impact Factor
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ABSTRACT: Two doses of measles-mumps-rubella (MMR) strategy has been recommended by World Health Organization and is also widely adopted in many countries. In order to provide the evidence for perfecting the immunization strategy of MMR, this study evaluated the safety and immunogenicity of MMR with different two-dose schedule in infants. 280 participants were enrolled and randomly allocated to Group 1 (first dose at 8 months) or Group 2 (first dose at 12 months), and both groups administered the second dose at 10 months later. Solicited local and general symptoms after each vaccination with MMR were mild and infrequent in all participants of two groups. After administration of the first dose of MMR, seropositive rates were 100% in both groups for measles, 89.3% in Group 1 and 87.1% in Group 2 for mumps (P=0.578), 92.0% in Group 1 and 92.9% in Group 2 (P=0.393). The seropositive rates of mumps decreased significantly (from >86% to <65%) both in two groups (P<0.001) 10 months after the first dose of MMR, but no significant change was found in measles and rubella. All children get the positive titer for three vaccines in two groups after given the second dose MMR, higher seroconversion rate was found for mumps both in two groups (71.7% vs 77.2%, P=0.370). In conclusion, this study indicated that the MMR was well tolerated and immunogenic against measles, mumps and rubella with schedule of first dose both at 8 months and 12 months age. Our findings strongly supported that two doses of MMR can be introduced by replacing the first dose of MR in current EPI with MMR at 8 months age and the second dose at 18 months in China.Vaccine 05/2014; DOI:10.1016/j.vaccine.2014.04.044 · 3.49 Impact Factor
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ABSTRACT: 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. The study utilized a cross-sectional study cohort of healthy children who had been immunized with one-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 EIA and considered seropositive if the EIA 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. 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. Asthma status is associated with waning kinetics of measles antibody among children.The Pediatric Infectious Disease Journal 05/2014; 33(10). DOI:10.1097/INF.0000000000000375 · 3.14 Impact Factor