Mumps vaccine hesitancy: Current evidence and an evidence-based campaign in Japan.

BACKGROUND: Mumps is still endemic in Japan because mumps vaccination is voluntary. In this study, we investigated associations of parental socioeconomic status, family structure, and knowledge/belief about mumps and mumps vaccine with parental decision to vaccinate their children. We also evaluated effectiveness of a campaign based on survey results. METHODS: We conducted a cross-sectional survey of parents with children aged 1-6 years attending preschools or kindergartens in Tokamachi City, Japan. We assessed the association of parental factors with their decision to vaccinate their children using multivariable logistic regression analyses. We designed a campaign based on the survey results, and compared the number of annual vaccinations at Tokamachi Hospital per the child population aged 1-6 years in Tokamachi City before and after the campaign using a trend test. RESULTS: In total, 1391 of 1617 (86%) eligible parents completed the survey. Among these parents, 229 (16%) vaccinated their children. In multivariable analyses, higher parental education [odds ratio (OR) = 2.21; 95% CI, 1.59-3.08; P < 0.001], greater knowledge about mumps and the mumps vaccine (OR = 1.88; 95% CI, 1.60-2.21; P < 0.001), and living without grandparents (OR = 1.44; 95% CI, 1.05-1.99; P = 0.024) were significantly associated with parental decision to vaccinate their children. The number of annual vaccinations per the child population significantly increased following the campaign (P < 0.001). CONCLUSION: Our study showed several sociodemographic factors significantly associated with mumps vaccination. Further research is needed to examine the relevance of our findings to the uptake of other voluntary vaccines among children.

Parvovirus B19: A Cause of Sepsislike Syndrome in an Infant.

Parvovirus B19 (PB19) is an important human pathogen that results in a wide spectrum of clinical outcomes, from mild, self-limiting erythema infectiosum in immunocompetent children and arthralgia in adults to lethal cytopenia in immunocompromised patients and intrauterine fetal death. However, there have been few reports of PB19 infection in neonates or young infants (aged 28-90 days), and no previous reports contained descriptions of PB19 infection as a cause of sepsislike syndrome in this age group. We report a case of sepsislike syndrome caused by PB19 infection in a 56-day-old infant whose mother had polyarthralgia at the time of his admission. PB19 infection was diagnosed on the basis of positive polymerase chain reaction results for PB19 DNA in the serum and cerebrospinal fluid. Positive immunoglobulin M and negative immunoglobulin G for PB19 suggested acute infection. He was admitted to the ICU because of poor peripheral circulation, but fully recovered without antibiotic administration. After excluding other possible pathogens, PB19 should be suspected as a cause of sepsislike syndrome in young infants, especially those who have close contact with PB19-infected individuals.

Amino acid substitution at position 464 in the haemagglutinin-neuraminidase protein of a mumps virus Urabe strain enhanced the virus growth in neuroblastoma SH-SY5Y cells.

Mumps virus (MuV) infects various organs including central nervous system (CNS). However, the molecular basis of the neural cell specificity of MuV is not well understood. We found that the Hoshino vaccine strain rescued from cDNA replicated moderately in neuroblastoma SH-SY5Y cell line, while an Urabe strain (Ur89-250) isolated from a post-vaccination aseptic meningitis case replicated efficiently in the same cells. In order to examine the contribution of individual genes of Ur89-250 to the growth in SH-SY5Y cells, recombinant Hoshino vaccine strains in which each gene(s) was replaced with corresponding gene(s) of Ur89-250 were generated. A recombinant virus possessing the small hydrophobic and haemagglutinin-neuraminidase (HN) genes of Ur89-250 grew as efficiently in SH-SY5Y cells as Ur89-250. Further analysis indicated that an amino acid substitution at position 464 in the HN protein was most important for efficient growth. Thus, single amino acid substitution in the HN protein could affect neural cell specificity of mumps virus.

Enhancing of measles virus infection by magnetofection.

Magnetofection is a viral and non-viral gene delivery method using polyethyleneimine-conjugated super-paramagnetic nanoparticle under a magnetic field. Previous studies have indicated that magnetofection enhanced the infection of adenoviruses and retroviruses. It is shown that magnetofection enhances the infection of measles virus, a paramyxovirus. When cells expressing a measles virus receptor human SLAM were infected with a measles virus that encodes green fluorescent protein gene, magnetofection enhanced measles virus infection by 30- to 70-fold. The infection of SLAM-negative cells with measles virus was also enhanced by magnetofection, but to a lesser extent. These results indicate that magnetofection could be useful for isolation of measles virus from clinical specimens.