Vaccination coverage among adolescents 1 year before the institution of a seventh grade school entry vaccination requirement--San Diego, California, 1998

In 1996, the Advisory Committee on Immunization Practices, the American Academy of Pediatrics, the American Association of Family Physicians, and the American Medical Association recommended routine health-care visits for children aged 11-12 years, emphasizing vaccination with hepatitis B vaccine; measles, mumps, and rubella vaccine (MMR); tetanus and diphtheria toxoids (Td); and varicella vaccine. Because no national data exist regarding vaccination coverage among adolescents, the impact of these recommendations is unknown. In October 1997, California enacted Assembly Bill 381 (AB381) that requires students entering the seventh grade on or after July 1, 1999, to have received three doses of hepatitis B vaccine and two doses of MMR. To assist in planning and implementing AB381, the San Diego County Health Department expanded its 1998 infant and adult vaccination survey to include fifth and sixth graders. This report summarizes the findings from that survey, which indicate that most fifth and sixth graders lacked required and recommended vaccinations.

Immunization status of children born to human immunodeficiency virus (HIV)-infected mothers in two Texas cities

BACKGROUND

Because HIV-infected and HIV-exposed children are at risk of acquiring infectious diseases, they should be immunized.

METHODS

We abstracted charts at pediatric HIV clinics in Dallas and San Antonio, matched the children to birth certificates and assessed up-to-date immunization status.

RESULTS

Of the 178 children, 108 (61%) were up to date for the diphtheria-tetanus-pertussis (DTP), polio, and measles-mumps-rubella (MMR) series. In multivariate analysis, predictors of delayed immunization included maternal high-risk sexual partners and infant antiretroviral therapy.

CONCLUSION

In this population of children born to HIV-infected mothers, immunizations were up to date in 61%, a figure that exceeds or equals immunization levels for other Texas children. Texas falls short of the recommended goal of 90% immunization for children of HIV-infected mothers and healthy children.

Sex differences in antibody- and cell-mediated immune response to rubella re-immunisation

Antibody (AMI) and cell-mediated (CMI) immunity to rubella virus (RV) were evaluated in healthy adolescent males (n = 11) and females (n = 28) undergoing routine reimmunisation with RA27/3 strain RV as a component of measles-mumps-rubella (MMR) vaccine. Blood samples were collected just before and at 2, 4 and 10 weeks after MMR. While there were no sex differences before MMR and at week 10 after vaccination, levels of specific IgG determined by whole RV enzyme immunoassay were found to be significantly higher in males at weeks 2 and 4, suggesting brisker onset of recall AMI. Analysis of RV protein-specific IgG by immunoblot assays also revealed that while there were no notable sex differences in the distribution of E1-specific antibodies, more males produced E2-specific antibodies whereas more females produced C-specific antibodies after immunisation. Analysis of CMI with whole inactivated RV and a panel of RV synthetic peptides in lymphocyte proliferation assays revealed a brisker onset of CMI in males which paralleled that observed for AMI. The numbers of RV antigens recognised by males were significantly higher at weeks 2 and 4. Also, mean and median stimulation indices measured at weeks 2 and 4 for certain peptides, including two known to contain overlapping antibody neutralisation domains and T-cell epitopes, E1(213-239) and E1(254-285), were also found to be significantly higher in male subjects. These observations suggest that there are hormonal influences on RV-specific immunity which might result in differential handling of RV and, hence, may partially explain why females are more predisposed to adverse outcomes of rubella infection and immunisation.

Opportunistic immunisation in hospital

AIM

To assess the potential for administering catch up and scheduled immunisations during hospital admission.

METHODS

Immunisation status according to the child's principal carer was checked against official records for 1000 consecutively admitted preschool age children. Junior doctors were instructed to offer appropriate vaccination before discharge, and consultants were asked to reinforce this proactive policy on ward rounds.

RESULTS

Excluding those children who were not fully immunised against pertussis through parental choice, 142 children (14.2%) had missed an age appropriate immunisation and 41 were due a scheduled immunisation. None had a valid contraindication. Only 43 children were offered vaccination on the ward but uptake was 65% in this group.

CONCLUSIONS

Admission to hospital provides opportunities for catch up and routine immunisations and can contribute to the health care of an often disadvantaged group of children. These opportunities are frequently missed. Junior doctors must be encouraged to see opportunistic immunisation as an important part of their routine work.

[Measles. A viral illness with risk of permanent damage]

Measles is a highly contagious exanthematous disease. After an incubation period of almost two weeks, catarrhal prodromic, associated with initial attacks of fever appear. Typical manifestations are Koplik's spots. The exanthema appears together with the second rise in temperature. The illness confers lifelong immunity. In individual cases, an encephalitis resulting in permanent neurological deficits must be expected. Every effort should be made to prevent this condition from arising. To this end, immunization with a combination measles, mumps, rubella (MMR) vaccine is recommended.

[Vaccination of children in 1999]

Childhood immunization programs are regularly reevaluated to take into account epidemiologic changes in the diseases covered by the vaccines as well as the development of new vaccines. Among the significant additions brought in Belgium to the childhood immunization program in recent years are immunization against hepatitis B during infancy, as well as the administration of a second dose of measle-mumps-rubella vaccine around the age of 12 years. The switch to inactivated polio vaccine will be proposed until the eradication of this disease which is expected in a few years. Combination vaccines including all injectable vaccines recommended for administration during the first year of life including acellular pertussis are in their final stage of development.

Immunization status of children enrolled in a hospital-based medicaid managed care practice: the importance of the timing of vaccine administration

OBJECTIVES

To evaluate the immunization status of children enrolled in a hospital-based Medicaid managed care practice and to assess the impact of the timing of vaccine administration on measured immunization rates.

DESIGN AND METHODS

The medical records of all children between the ages of 19 and 35 months who were continuously enrolled in the Medicaid managed care practice for the last 6 months of 1996 were reviewed. Immunization status was determined for the following vaccines: diphtheria-tetanus-pertussis/diphtheria-tetanus-acellular pertussis (4 doses); Haemophilus influenzae type b (3 doses); poliovirus (3 doses); hepatitis B (3 doses); measles-mumps-rubella (1 dose); and overall for the basic series. Two assessment methods were used to determine the immunization status of the study children: (1) a count of all documented vaccines ("count"); and (2) only including vaccines that met minimal age and spacing intervals based on American Academy of Pediatrics and CDC recommendations ("interval assessment").

RESULTS

With the count method vaccine-specific immunization rates ranged from 88 to 95%, with overall coverage of 80% for the basic series. With the interval assessment method vaccine-specific immunization rates ranged from 74 to 92%, with overall coverage of 53% for the basic series.

CONCLUSIONS

When all documented vaccines were included in the assessment, vaccine-specific immunization rates approached national goals, although overall coverage remained below 90% in this Medicaid managed care practice. The substantially lower immunization rates obtained by the interval assessment method demonstrate the importance of considering the issue of vaccine timing when interpreting immunization rates and the need for policies for revaccinating children who were immunized at less than recommended intervals. The results also have implications for provider education regarding the early administration of vaccines.

A randomized comparative trial in order to assess the reactogenicity and immunogenicity of a new measles mumps rubella (MMR) vaccine when given as a first dose at 12-24 months of age

An open, randomized multi-center trial, involving 700 infants, was conducted in order to compare a new measles mumps rubella (MMR) vaccine, SB MMR (containing a Jeryl Lynn derived mumps strain RIT 4385) with a widely used vaccine, Merck MMR, when given to children between 12-24 months. Infants were divided between 2 groups; group 1 received SB MMR while group 2 received Merck MMR. Solicited local and general symptoms were recorded using diary cards and antibody levels were measured using ELISA assays. There was a significantly lower incidence of redness (p < 0.001) and swelling (p = 0.03) observed in group 1 compared with group 2. The incidence of all other solicited local and general symptoms were comparable between groups. In initially seronegative subjects equivalent seroconversion rates and post-vaccination GMTs were observed between groups. In conclusion, these results demonstrate that SB MMR is safe and well tolerated when given to children at this age range, and has an equivalent immunogenic profile compared to the widely used Merck MMR vaccine.

Estimation of the direct and indirect effects of vaccination

Indirect effects play a major role in the protection afforded by a vaccination programme. In this work we define new measures of direct, indirect and total (direct + indirect) effects of a vaccination programme in terms of the protection they provide to unvaccinated and vaccinated individuals, and to the entire population. We show how these measures can be estimated using data from a vaccine trial or an observational study. The bias and standard errors of these estimates can be evaluated via stochastic simulations. Examples from a mumps outbreak and a (hypothetical) HIV vaccine trial are used to illustrate the estimation of these new measures of vaccination effectiveness.

Mumps: a current epidemiologic pattern as a necessary background for the choice of a vaccination strategy

Before the measles mumps rubella (MMR) vaccination was widely offered, the epidemiologic data about mumps (morbidity, immunization level, vaccine coverage) were analyzed in Piedmont region (Italy). The disease had a 3- to 5-year epidemic recurrence with morbidity rate between 40 and 150/100,000; the surveillance conducted by 'sentinel' pediatricians showed that the notifications underestimated the real data by about 5- to 7-fold. The 12-year-old subjects showed an immunization level (reached by the disease or the vaccination) of about 50% and their parents tended to refuse the MMR vaccination. Only 54% of the 3- to 5-year-old children received the MMR vaccine in the second year of life and the frequency of the vaccination failure was about 10%. The strategy of vaccination should take into account this epidemiologic pattern, to program an offer adequate to reach mumps control/elimination; the strategy of our region should include the active offer in the second year of life to reach higher coverage, a second offer at 4-6 and/or 12 years of life, when other vaccinations are given and the choice of a highly efficacious vaccine. The improvement of the notification system could also allow a more sensitive surveillance of epidemiologic patterns.

Evaluation of serological status of rubella & mumps in children below five years

A cross-sectional study was carried out on 321 serum samples to detect rubella and mumps antibodies in children below five years and to assess the optimum age for immunization against rubella and mumps. Seropositivity to rubella was 33.3 per cent in children below nine months, 16.9 per cent at 9-12 months and 25.5 per cent by two years. Mean antibody levels for rubella were low at nine months to one year and remained so till five years of age. Similarly, seropositivity for mumps was 53.3 per cent below nine months, 20.3 per cent at 9-12 months and 40 per cent by two years. Mean antibody levels for mumps were low between nine months to two years with a slight rise by five years. The findings suggest that a large majority of children are at risk by the age of nine months in our population and the measles, mumps and rubella (MMR) vaccination at this age may be most beneficial.

Increased protections during a measles outbreak of children previously vaccinated with a second dose of measles-mumps-rubella vaccine

BACKGROUND

In 1989 a second dose of measles vaccine was recommended for US children to prevent school outbreaks of measles. Coverage of school age children with a second dose remains incomplete, and data on the effectiveness of this recommendation are limited. We investigated a measles outbreak in Mesa County, CO, in December, 1994, and evaluated the efficacy of preoutbreak immunizations at an elementary school (School A) where many students had received two doses.

METHODS

All reported suspected cases of measles were investigated; cases that met a clinical case definition were tested by a measles IgM antibody assay. A confirmed case required laboratory confirmation or had to meet the clinical case definition and be epidemiologically linked to a confirmed case. Vaccination records of students at School A were reviewed. The effectiveness of one and two doses of measles vaccine was estimated using logistic regression.

RESULTS

Sixty-two confirmed cases were reported, including 17 at School A. At School A the attack rate in unvaccinated children (7 of 16, 44%) was higher than in those with 1 dose (10 of 320, 3%) or 2 doses (0 of 289, 0%). Estimated vaccine effectiveness was 92% for 1 dose and 100% for 2 doses. Two doses were better than one dose in decreasing the likelihood of acquiring measles (P = 0.003).

CONCLUSIONS

The lower attack rate among two dose recipients provides evidence that a two dose strategy can help prevent measles in schools. Administering the second dose at elementary school entry can help prevent the persistence of susceptible cohorts of children and is likely to be important in sustaining elimination of indigenous transmission of measles in the United States.

[Community effectiveness of vaccines against infectious parotiditis (mumps). Report of cases]

BACKGROUND

In our country, there are two types of infectious mumps vaccines available. In recent times, doubts have been raised regarding the overall effectiveness of these vaccines and the comparative effectiveness of the two strains (Rubini strain and Jeryl Lynn strain). In the "East Seville" Primary Care district, 245 cases were reported in 1997 (90.1 cases per 100,000 inhabitants). This study is aimed at taking advantage of the outbreak of cases of mumps to evaluate affected populations and comparative incidence according to type of vaccines given during childhood.

METHODS

Descriptive analysis of the cases (age, territorial spread, inoculation history') and trend analysis (annual incident rates) within this health care district and the surrounding area. The overall effectiveness of the mumps vaccines. The case incidence rates among those inoculated with Rubini strain and those inoculated with Jeryl Lynn strain are also estimated.

RESULTS

The highest rates of incidence are found among children in the 1-4 age range. Overall effectiveness rates for these vaccines have been estimated. A significantly higher rate of infection has been found among the children inoculated with Rubini strain than those inoculated with the Jeryl Lynn strain (relative risk of 6.5 with a Confidence Interval of 95% 3.6-11.8).

CONCLUSIONS

The effectiveness which follows from this study does not seem as good as the theoretical effectiveness anticipated for the mumps vaccines. It thus seems advisable for other case studies to be conducted by types of vaccines used. The data to be furnished by means of sero-epidemiological studies are also of major interest.

[Measles, mumps and rubella: vaccination rate and seroprevalence in 8th grade students of 8 different sites in Switzerland 1995/96]

In 1987, the Swiss Federal Health Office (BAG) and the Swiss cantons launched the MMR-vaccination campaign. Within the frame of the SCARPOL Study, the vaccination status of 649, 8th class students was registered and serum samples were collected. The measles, mumps and rubella specific antibody levels were determined. The vaccination rate was 84% for measles, 74% for mumps, and 62% for rubella, 55% of these children had been vaccinated with the combined vaccine MMR. The vaccination rate for the different study areas varied from 70% to 95% for measles, 42% to 94% for mumps and 18% to 89% for rubella, 92% of the children tested seropositive for measles specific antibodies, 87% for mumps and 84% for rubella. The seroprevalence for measles, mumps and rubella was significantly higher for vaccinated than for unvaccinated children. Non-Swiss children had, without exception, a higher seroprevalence rate than Swiss children. Undergoing the disease did not influence the seroprevalence for measles, but it did so for mumps and rubella, for vaccinated and unvaccinated children alike. By analysis according to study site, we observed that sites with higher vaccination rates (e.g. Grabs in Rheintal) sometimes showed a lower seroprevalence than sites with lower vaccination rates (e.g. Langnau). This was the case for all three vaccines. This, together with other observations, shows that a booster is necessary for an adequate immunisation--as a wild virus infection or as a second vaccination.

Are vaccination rates higher if providers receive free vaccines and follow contraindication guidelines?

BACKGROUND AND OBJECTIVES

Economics has been suggested as a barrier to vaccination, but data that link clinician reports to actual immunization rates are limited. This study examined the relationship between clinicians' self-report regarding likelihood of vaccinating and actual age at vaccination from a registry of children seen by the clinicians.

METHODS

Standardized telephone survey results of 29 providers were compared to the immunization records of children seeing these providers, using analysis of contingency tables (on time versus late) and conditional hierarchical linear models with log age at diphtheria-tetanus-pertussis (DTP)#3, DTP#4, and measles-mumps-rubella (MMR)#1 as the dependent variables.

RESULTS

Children seeing providers likely to refer an uninsured child for immunization were vaccinated at a later log age at DTP#4 but not for DTP#3 or MMR#1 than children seeing providers unlikely to refer. Vaccination rates were higher for MMR#1 (77% versus 48%), DTP#3 (84% versus 71%), and DTP#4 (82% versus 66%) among providers who received free vaccine, compared with children seen by providers who did not receive free vaccine. These results remained significant in the hierarchical analyses. Providers likely to vaccinate an 18-month-old with watery diarrhea had higher vaccination rates than those unlikely to vaccinate for MMR#1, DTP#3, and DTP#4; the results were also significant in the hierarchical analyses.

CONCLUSION

Children are vaccinated later in the practices of providers who are likely to refer uninsured children to a public vaccine clinic for vaccination, who do not receive free vaccine supplies, or who overinterpret contraindications.

Comparison of immunogenicity of simultaneous and nonsimultaneous vaccination with MMR and JE vaccine among 15-month-old children

To evaluate the immunogenicity of measles- mumps- rubella (MMR) vaccination with Japanese encephalitis (JE) vaccine nonsimultaneously and simultaneously, 145 babies, aged 15 months were enrolled into two groups. Group A received MMR and JE vaccines nonsimultaneously at an interval of 6 weeks; group B received the vaccinations simultaneously. Antibody titers of MMR and JE were detected before and 8 weeks after vaccination. A total of 118 babies (61 in group A; 57 in group B) completed the study. In group A, mean increments of logarithmic geometric mean titers (GMTs) of MMR and JE were 4.51, 5.93, 4.07 and 1.99; seroresponse rates were 100% (61/61), 77.05% (47/61), 96.72% (59/61) and 59.02% (36/61) respectively. In group B, mean increments of logarithmic GMTs of MMR and JE were 4.35, 5.37, 4.44 and 1.93; seroresponse rates were 98.25% (56/57), 77.19% (44/57), 98.25% (56/57) and 57.89% (33/57) respectively. There were no significant differences between these two groups. These results suggest that simultaneous and nonsimultaneous vaccination with MMR and JE vaccines were similar in immunogenicity.

Minimum time interval adjustment for 4-3-1 immunization rates among two-year-old children

BACKGROUND

The purpose is to determine the administrative validity of the 4-3-1 immunization rates for DPT-OPV-MMR vaccines for 2-year-old children in a community health status assessment project by accounting for premature administration of specific vaccine doses according to ACIP recommended minimal timing intervals.

METHODS

A retrospective survey of immunization certificates was made on a random sample of 1,059 kindergarten enrollees in the county, including public, private, and parochial schools. The immunization rates by the crude 4-3-1 counting method were compared with the same method adjusted for minimal time interval vaccine dosing.

RESULTS

By the crude 4-3-1 counting method, 55.5% of the students had complete immunizations by their second birthdate, and 11.8% did not meet the minimum interval recommendations on at least one of 4-3-1 vaccine series. The adjustment for minimum time interval reduced the percent in compliance with the 4-3-1 counting method by age 2 in the community to 50.7%.

CONCLUSION

The premature timing of vaccine doses is a threat to the validity of the 4-3-1 counting method. The crude 4-3-1 method over-estimates the completed immunization rates for 2-year-olds in this community-based study by about 4.8%.