Measles in Europe--there is room for improvement

Measles, mumps and rubella (MMR) vaccination has no effect on cognitive development in children - the results of the Polish prospective cohort study

OBJECTIVES

The aim of the study was to examine the hypothesis that MMR exposure has a negative influence on cognitive development in children. Furthermore, MMR was compared to single measles vaccine to determine the potential difference of these vaccines safety regarding children's cognitive development.

METHODS

The prospective birth cohort study with sample consisted of 369 infants born in Krakow. Vaccination history against measles (date and the type of the vaccine) was extracted from physicians' records. Child development was assessed using the Bayley Scales of Infant Development (BSID-II) up to 3rd year of life, Raven test in 5th and 8th year and Wechsler (WISC-R) in 6th and 7th year. Data on possible confounders came from mothers' interview, medical records and analyses of lead and mercury level at birth and at the end of 5th year of life. Linear and logistic regression models adjusted for potential confounders were used to assess the association.

RESULTS

No significant differences in cognitive and intelligence tests results were observed between children vaccinated with MMR and those not vaccinated up to the end of the 2nd year of life. Children vaccinated with MMR had significantly higher Mental BSID-II Index (MDI) in the 36th month than those vaccinated with single measles vaccine (103.8±10.3 vs. 97.2±11.2, p=0.004). Neither results of Raven test nor WISC-R were significantly different between groups of children vaccinated with MMR and with single measles vaccine. After standardization to child's gender, maternal education, family economical status, maternal IQ, birth order and passive smoking all developmental tests were statistically insignificant.

CONCLUSION

The results suggest that there is no relationship between MMR exposure and children's cognitive development. Furthermore, the safety of triple MMR is the same as the single measles vaccine with respect to cognitive development.

Two consecutive measles outbreaks with genotypes D8 and D4 in two mainly unvaccinated communities in Germany

A measles infection in a 13-year-old student from a free progressive school was the index case for an outbreak in Essen in 2010. In this type of school, mainly unvaccinated and measles-susceptible children accumulate. This observation is confirmed by the fact that some of the recent outbreaks originated in such institutions. In Essen, this outbreak was followed by a second smaller outbreak in unvaccinated children and adults in a low socio-economic setting and migration background. Measles were diagnosed clinically and/or were serologically confirmed. Genotyping of measles isolates was performed by PCR and sequencing. Vaccination certificates were checked by the Community Health Centre (CHC) of the City of Essen. Measures to prevent the spread of the infection were implemented and enforced according to the National Protection Against Infection Act (IfSG). In total, 86 cases of measles were notified from March to July 2010. Of all infected patients, 97 % had had no vaccination and 15 % had to be hospitalised. Clinical courses showed the severity of this infection. Epidemiologic evaluation and genotyping of measles virus (MV) detected in Essen revealed the presence of two distinct chains of MV transmission by genotypes D8 and D4 causing two independent outbreaks. The outbreaks were caused by the index cases, and the spread of infection was facilitated by insufficient vaccination coverage in certain groups. Immediate suspension of non-immune children from classes for 2 weeks might have limited the outbreak in the free progressive school. Overall, high measles vaccination coverage in children and adolescents in regular schools in Essen presumably prevented a greater spread of the virus.

Non-nucleoside inhibitors of the measles virus RNA-dependent RNA polymerase: synthesis, structure-activity relationships, and pharmacokinetics

The measles virus (MeV), a member of the paramyxovirus family, is an important cause of pediatric morbidity and mortality worldwide. In an effort to provide therapeutic treatments for improved measles management, we previously identified a small, non-nucleoside organic inhibitor of the viral RNA-dependent RNA polymerase by means of high-throughput screening. Subsequent structure-activity relationship (SAR) studies around the corresponding pyrazole carboxamide scaffold led to the discovery of 2 (AS-136a), a first generation lead with low nanomolar potency against life MeV and attractive physical properties suitable for development. However, its poor water solubility and low oral bioavailability (F) in rat suggested that the lead could benefit from further SAR studies to improve the biophysical characteristics of the compound. Optimization of in vitro potency and aqueous solubility led to the discovery of 2o (ERDRP-00519), a potent inhibitor of MeV (EC(50) = 60 nM) with an aqueous solubility of approximately 60 μg/mL. The agent shows a 10-fold exposure (AUC/C(max)) increase in the rat model relative to 2, displays near dose proportionality in the range of 10-50 mg/kg, and exhibits good oral bioavailability (F = 39%). The significant solubility increase appears linked to the improved oral bioavailability.

U.K. parents' decision-making about measles-mumps-rubella (MMR) vaccine 10 years after the MMR-autism controversy: a qualitative analysis

BACKGROUND AND OBJECTIVES

Public concern about an unsubstantiated link between MMR vaccine and autism stemmed from a 1998 paper by Dr Andrew Wakefield and colleagues, and the substantial media coverage which that work attracted. Though the Wakefield paper is now discredited and an MMR-autism link has never been demonstrated empirically, this concern has manifested in over a decade of suboptimal MMR uptake. Few qualitative studies have explored parents' MMR decision-making since uptake began to improve in 2004. This study updates and adds methodological rigour to the evidence base.

METHODS

24 mothers planning to accept, postpone or decline the first MMR dose (MMR1) for their 11-36 month-old children, described their decision-making in semi-structured interviews. Mothers were recruited via General Practice, parents' groups/online forums, and chain referral. MMR1 status was obtained from General Practice records 6 months post-interview. Interview transcripts were coded and interpreted using a modified Grounded Theory approach.

RESULTS

Five themes were identified: MMR vaccine and controversy; Social and personal consequences of MMR decision; Health professionals and policy; Severity and prevalence of measles, mumps and rubella infections; Information about MMR and alternatives. Results indicated that MMR1 acceptors were sympathetic toward Wakefield as a person, but universally rejected his study which sparked the controversy; parents opting for single vaccines expressed the sense that immune overload is not a consideration but that not all three components of MMR are warranted by disease severity; and MMR1 rejectors openly criticised other parents' MMR decisions and decision-making.

CONCLUSIONS

This study corroborated some previous qualitative work but indicated that the shrinking group of parents now rejecting MMR comprises mainly those with more extreme and complex anti-immunisation views, whilst parents opting for single vaccines may use second-hand information about the controversy. In response, policymakers and practitioners should revise their expectations of today's MMR decision-makers, and their methods for supporting them.

Who are the children at risk? Lessons learned from measles outbreaks

We investigated a measles outbreak in the Jerusalem district in 2007-2008 (992 cases). Most cases (72·6%) were aged <15 years, 42·9% aged <5 years, and 12·8% were infants aged <1 year. The peak incidence rate was in infants aged 6-12 months (916·2/100 000). This represents a significant shift from former outbreaks in 2003-2004, where the peak incidence was in the 1-4 years age group. Of children aged <5 years the proportion aged 6-12 months tripled (7·7% vs. 25·6%). In a case-control study (74 cases, 148 controls) children who developed measles were less likely to be registered in a well-baby clinic and had lower overall immunization coverage. The differences in proportions for registration, DTaP3 and MMR1 coverage were 35·1%, 48·6% and 80·8%, respectively (all P<0·001). Rising birth order of cases and their siblings was associated with non-registration and non-compliance with MMR immunization. The vulnerability of young infants and the risk markers noted above should be taken into account in planning intervention programmes.

Communicable Diseases: Achievements and Challenges for Public Health

The past two centuries have seen enormous achievements in control of infectious diseases, previously the leading cause of death, in large measure due to sanitation and food safety, vaccines, antibiotics and improved nutrition. This has led people to put their faith in the notion that medical science would succeed in overcoming the remaining obstacles. Vaccination has eradicated smallpox, nearly eradicated poliomyelitis and greatly reduced many other highly dangerous infections such as diphtheria, tetanus and measles. New diseases such as HIV and new forms of influenza have taken both professional and popular opinion by surprise and have renewed the challenges before the world public health community. Emergence of antibiotic-resistant strains of common organisms due to overuse of antibiotics and lack of vaccines for many dangerous microorganisms poses problems to humanity. This stresses the need for new vaccines, effective antibiotics and strengthened environmental control measures. New knowledge of the microbiological origins of cancers such as that of the cervix, stomach and liver have strengthened primary prevention and brought hope that new cures will be found for other chronic diseases of infectious origin. Tragically long delays in adopting "new" and cost effective vaccines cause hundreds of thousands of preventable deaths each year in developing and mid-level developed countries. Gains are being made in control of many tropical diseases, but malaria, tuberculosis and other infectious diseases remain enormous global problems. Research and acquisition of new knowledge, risk communication, application of currently available means and fair distribution will be great challenges to public health in the coming decades.

Target analysis of the experimental measles therapeutic AS-136A

No effective therapeutic is currently in place for improved case management of severe measles or the rapid control of outbreaks. Through high-throughput screening, we recently identified a novel small-molecule class that potently blocks activity of the measles virus (MeV) RNA-dependent RNA polymerase (RdRp) complex in transient replicon assays. However, the nature of the block in RdRp activity and the physical target of the compound remained elusive. Through real-time reverse transcription-PCR analysis, we demonstrate that the lead compound AS-136A blocks viral RNA synthesis in the context of an infection. Adaptation of different MeV strains to growth in the presence of the compound identified three candidate hot spots for resistance that are located in conserved domains of the viral polymerase (L protein) subunit of the RdRp complex. Rebuilding of individual mutations in RdRp-driven reporter assays and recombinant MeV traced the molecular basis for resistance to specific mutations in L. Mutations responsible for resistance cluster in the immediate vicinity of the proposed catalytic center for phosphodiester bond formation and neighboring conserved domains of L, providing support for effective inhibition of a paramyxovirus RdRp complex through interaction of a nonnucleoside small-molecule inhibitor with the L protein. Resistance mutations are located in regions of L that are fully conserved among viral isolates, and recombinant MeV harboring individual resistance mutations show some delay in the onset of viral growth in vitro. Taken together, these data support the hypothesis that acquiring mutations in these L domains may reduce virus fitness.