The new measles campaign

The historical aspects of vaccination in pregnancy

As we live through the history-making pandemic of coronavirus disease 2019 (COVID-19), it is timely to consider the lessons that history has taught us about vaccine-preventable disease in pregnancy. Vaccinations have earned an established place in pregnancy care to prevent communicable disease in the mother, fetus and newborn. The improvements in maternal and perinatal outcome have been achieved through the evolution and application of new knowledge in many areas. These include recognition of the unique pathogenic consequences of diseases in pregnancy; improved understanding of the maternal immune system and its interplay with the fetus; optimizing safe vaccine development; ensuring pregnant women are included in appropriately designed trials of efficacy, and public health engagement to optimize uptake. As the world eagerly awaits an effective vaccine for COVID 19, these lessons of history help signpost the way, to ensure the potential of vaccinations to reduce morbidity for pregnant women and their newborns is fully realized.

Impact on Epidemic Measles of Vaccination Campaigns Triggered by Disease Outbreaks or Serosurveys: A Modeling Study

BACKGROUND

Routine vaccination supplemented by planned campaigns occurring at 2-5 y intervals is the core of current measles control and elimination efforts. Yet, large, unexpected outbreaks still occur, even when control measures appear effective. Supplementing these activities with mass vaccination campaigns triggered when low levels of measles immunity are observed in a sample of the population (i.e., serosurveys) or incident measles cases occur may provide a way to limit the size of outbreaks.

METHODS AND FINDINGS

Measles incidence was simulated using stochastic age-structured epidemic models in settings conducive to high or low measles incidence, roughly reflecting demographic contexts and measles vaccination coverage of four heterogeneous countries: Nepal, Niger, Yemen, and Zambia. Uncertainty in underlying vaccination rates was modeled. Scenarios with case- or serosurvey-triggered campaigns reaching 20% of the susceptible population were compared to scenarios without triggered campaigns. The best performing of the tested case-triggered campaigns prevent an average of 28,613 (95% CI 25,722-31,505) cases over 15 y in our highest incidence setting and 599 (95% CI 464-735) cases in the lowest incidence setting. Serosurvey-triggered campaigns can prevent 89,173 (95% CI, 86,768-91,577) and 744 (612-876) cases, respectively, but are triggered yearly in high-incidence settings. Triggered campaigns reduce the highest cumulative incidence seen in simulations by up to 80%. While the scenarios considered in this strategic modeling exercise are reflective of real populations, the exact quantitative interpretation of the results is limited by the simplifications in country structure, vaccination policy, and surveillance system performance. Careful investigation into the cost-effectiveness in different contexts would be essential before moving forward with implementation.

CONCLUSIONS

Serologically triggered campaigns could help prevent severe epidemics in the face of epidemiological and vaccination uncertainty. Hence, small-scale serology may serve as the basis for effective adaptive public health strategies, although, in high-incidence settings, case-triggered approaches are likely more efficient.

Impact assessment of mass measles vaccination

OBJECTIVE

The mass measles vaccination campaign was conducted in the slums of Surat City, in Gujarat State, as a part of urban measles control initiative in India. One dose each of the vaccine was administered to children in the age range of 9-59 months residing in these slums, regardless of their previous vaccination status.

METHODS

One year later, (October 2000), the present study was carried out in order to assess the impact of the mass vaccination campaign on the vaccination coverage and on the incidence of measles by comparing the findings with those of the baseline survey carried out in May 98. This was a retrospective study with a recall period of the preceding year. 3,147 children under five were studied in thirty slum clusters selected by the cluster sampling method. The parents/caretakers of these children were interviewed for information on any episode of fever with rash conforming to the case definition.

RESULT

The incidence rate for measles declined from 7.7 percent reported in the baseline (May 1998) to 3.5 percent in the impact assessment study. The incidence was 8 times higher in unvaccinated children. The mean and median age at contracting the illness increased from 26 +/- 14.2 months and 26 months in the baseline to 30.9 +/- 14.7 months and 30 months respectively in the impact assessment. The vaccination coverage had improved from 48.3 percent to 73.7 percent following the campaign.

CONCLUSION

The compaign increased vaccination coverage decreased disease incidence and caused a shift towards higher age-groups in vaccinated children.

Causes of morbilliform rash in a highly immunised English population

AIMS

To determine the causes of morbilliform rash and fever in a population with high vaccination coverage for measles and rubella.

METHODS

Comprehensive laboratory investigation additional to routine oral fluid testing of children presenting to primary care physicians in East Anglia, England.

RESULTS

Laboratory confirmation of infection was obtained in 93 (48%) of 195 children: parvovirus B19 in 34 (17%); group A streptococcus in 30 (15%); human herpesvirus type 6 in 11 (6%); enterovirus in nine (5%); adenovirus in seven (4%); and group C streptococcus in six (3%) (four individuals tested positive for two agents). None had measles or rubella.

CONCLUSIONS

Oral fluid testing to cover infections additional to measles and rubella aids clinical management and is likely to maintain uptake of testing, which is essential for measles and rubella surveillance in highly immunised low incidence populations.

A retrospective cohort study of risk factors for missing preschool booster immunisation

AIM

To identify factors associated with non-uptake of preschool booster immunisation.

DESIGN

Data from the computerised child health system was used to study all children born in 1990 and living in South Glamorgan, Wales, on their 5th birthday. Factors associated with preschool booster uptake were investigated using multiple logistic regression.

RESULTS

Preschool booster coverage in the study cohort was 91.4%. After adjustment for other variables, uptake was associated most strongly with completed primary immunisation for diphtheria, tetanus, and polio vaccine or first dose measles, mumps, and rubella vaccine. Identifying children who miss either of these predicts 52.4% of those who miss the preschool booster.

CONCLUSION

Effective targeting of children who have missed previous immunisations could improve preschool booster uptake and ensure maximum uptake of at least one dose of measles, mumps, and rubella vaccine. Achieving optimum measles vaccine coverage is vital to achieve the goal of measles elimination.

[Measles outbreaks: considerations apropos of the outbreaks investigated in Catalonia (1990-1995)]

OBJECTIVES

To determine the factors associated with outbreak size in Catalonia.

METHODS

Outbreaks over the period 1990-95 were investigated. A comparison was run between outbreaks of more than 6 cases with respect to outbreaks of 2-6 cases in function of the following variables: median age of cases, transmission setting and year of presentation. Multiple logistic regression was used to asses the independent effect of each variable, with the adjusted odds ratio (ORa) and their 95% confidence interval (CI) being obtained.

RESULTS

In all, 45 outbreaks were studied, with 595 cases of measles 39.5% of outbreaks occurred in the 6-10 age group. Outbreaks of more than 6 cases had a higher likelihood of appearing in a school setting (ORa = 4.3, CI 95% 1.0-17.6); but there were no association with age (ORa = 2.1, CI 95% 0.5-9.2) or occurring prior to 1994 (ORa = 0.9, CI 95% 0.2-3.6).

CONCLUSIONS

School setting determines the outbreak size of measles and demands to apply specific preventive strategies.

Bilateral cytomegalovirus retinitis in a patient with systemic lupus erythematosus

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A study of maternally derived measles antibody in infants born to naturally infected and vaccinated women

Maternal, cord and infant measles antibody levels were measured and compared in a group of 411 vaccinated mothers and 240 unvaccinated mothers, and their babies, between 1983 and 1991. Maternal and cord sera were tested by haemagglutination inhibition and/or enzyme-linked immunosorbent assay, and plaque reduction neutralization tests were also used to test infant sera. Geometric mean titres were significantly higher in the unvaccinated than in the vaccinated mothers (P < 0.001). Infants born to mothers with a history of measles had higher antibody levels at birth than infants of vaccinated mothers and, although the difference narrowed over time, continued to have higher levels up to 30 weeks of age. Between 5 and 7 months of age significantly more of the children of vaccinated mothers had plaque reduction neutralization antibody levels below that which would interfere with vaccination. As the boosting effect of circulating natural measles disappears, earlier measles vaccination may need to be considered, perhaps as part of a two-dose policy.

Optic neuritis following measles/rubella vaccination in two 13-year-old children

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Serologic response to measles-mumps-rubella vaccine among children with upper respiratory tract infection

The influence of concurrent upper respiratory tract infection (URTI) on immune response to MMR (measles, mumps, rubella) vaccine was evaluated by measuring IgG levels for each viral component immediately before vaccination and 6 months after vaccination in 198 12-month-old children (101 children without URTI and 97 with URTI at time of vaccination). None of the children had antibodies to measles, mumps or rubella before vaccination. Seroconversion rates and the geometric means of the antibody titers in children without URTI and in children with URTI at the time of vaccination were similar. MMR vaccination should not be delayed in children with such infections.

Rubella immunity and morbidity: impact of different vaccination programs in Finland 1979-1992

As the previous vaccination of 11- to 13-year-old girls proved ineffective, nationwide vaccination of preschool children with 2 doses of combined vaccine against measles, mumps, and rubella was started in Finland in 1982. To study the impact of vaccination, age-stratified rubella immunity and the occurrence of serologically verified rubella cases were determined using the computerized data of our diagnostic virus laboratory. The analysis covered the period 1979-1992, included all ages, and was based on the test results from 94,000 sera. By 1992, the seropositivity rate was 92-100% in 2- to 15-year-old children, remained high in females of all ages, but showed a gap in 16- to 19-year-old males. The number of verified rubella cases decreased to about 1/100, but outbreaks still occurred until 1991, when most cases were among adolescent males. The better protection of women was due to the vaccination of prepubertal girls since 1975. No congenital rubella infections were diagnosed after 1986. The 2-dose immunization of preschool children, complemented by selective vaccination of certain other groups, has resulted in excellent immunity in children and young adults, and practically eliminated rubella from the country.

Priorities in global measles control: report of an outbreak in N'Djamena, Chad

In N'Djamena, capital of Chad, measles vaccination coverage of 12-23-month-old children fell from 61% in 1990 to 15% in 1993. A community survey of measles after an outbreak in 1993 showed that among children < 5 years of age, the mean monthly attack rate was 37 per 1,000 (95% CI, 32-43) and the mean case fatality rate was 7.4%. Measles incidence was highest (77/1,000/month) in children aged 9-11 months and fell among children > 3 years of age. Incidence rates were high (56/1,000/month) among 6-8-month-old children, but only 3 deaths occurred in this age group. Measles vaccine efficacy, estimated by comparing attack rates in unvaccinated and vaccinated children, was 71% (95% CI, 59-80%). Extrapolation of the results to the city population indicated that an estimated 19,000 cases and > 1,000 measles-associated deaths occurred in 1993. This preventable morbidity and mortality, in a city where coverage was formerly among the highest in Africa, shows the need for sustained global commitment to preventive health care.

Interpretation of serological surveillance data for measles using mathematical models: implications for vaccine strategy

Serological surveillance of measles immunity has been carried out in England since 1986/7. Results from sera collected in 1989-91 revealed that the proportion of school age children who were susceptible to measles was increasing, following the introduction of the measles, mumps and rubella vaccination programme in October 1988. Mathematical models are used to interpret these data and determine whether this increasing susceptibility is sufficient to allow a resurgence of disease from the low levels achieved by 1993. The models summarize serological profiles by a single parameter, the reproduction number R, which quantifies the level of herd immunity in the population. Results showed that there was cause for concern over the levels of susceptibility to measles, with an epidemic of over 100,000 cases likely in 1995/6. These predictions are consistent with trends in the incidence and age distribution of measles and have enabled the planning of a major vaccination campaign.