Controlling invasive pneumococcal disease: is vaccination of at-risk groups sufficient?

Risk factors for invasive pneumococcal disease (IPD) include young and old age, comorbidities (such as splenic dysfunction, immunodeficiencies, chronic renal disease, chronic heart or lung disease or cerebral spinal fluid leak), crowded environments or poor socioeconomic conditions. Universal use of the 7-valent pneumococcal conjugate (7vPncCRM) vaccine for infants and young children has led to significant decreases in IPD in the vaccinated population (direct protection), and there has also been a decrease in the incidence of IPD among the nonvaccinated population (indirect immunity; herd protection). While 7vPncCRM vaccine is administered universally to children in USA, many countries of the European Union have chosen to target children with comorbidities. This review aims to highlight individual risk factors for IPD, describe studies that evaluated pneumococcal conjugate vaccines in at-risk groups and estimate the proportion of at-risk children who may have been vaccinated in the European Union since the 7vPncCRM vaccine was introduced, using UK as an example. Although immunisation targeting only children with comorbidities may achieve satisfactory results for a few, many otherwise healthy children at risk simply because of their age will be neglected, and herd protection might not be established.

Safety and immunogenicity of a combined live attenuated measles, mumps, rubella, and varicella vaccine (MMR(II)V) in healthy children

An investigational tetravalent combined measles, mumps, rubella, and varicella vaccine and measles-mumps-rubella and varicella vaccines at separate injection sites given at the same visit were evaluated with respect to safety and cell-mediated and humoral immune responses at 6 weeks and 1 year after vaccination. Varicella seroconversion rates and lymphocyte proliferation responses were 100% for both vaccine groups at 6 weeks and 1 year. However, the antibody titer to varicella was lower in the combined vaccine group at 6 weeks, but there was no statistical difference in cell-mediated immune responses. One-year geometric mean titers were not statistically different. Seroconversion rates for measles, mumps, and rubella were 100% for both vaccine at 6 weeks and 1 year. Long-term follow-up of these immune responses is planned.

Resistance to antivirals

The ability of viruses to develop resistance to antiviral agents is already a major concern with respect to HIV. This article reviews mechanisms and clinical correlates of antiviral resistance and alternative drugs for treatment of infections due to resistant strains of HIV, herpes simplex virus, cytomegalovirus, varicellazoster virus, and influenza A.

Saliva and serum as diagnostic media for antibody to hepatitis A virus in adults and in individuals who have received an inactivated hepatitis A vaccine

Saliva was evaluated as a diagnostic fluid for screening individuals for evidence of previous hepatitis A virus (HAV) infection and for evidence of seroconversion after vaccination with inactivated hepatitis A vaccine. A new and simple saliva collection method and an assay for detection of HAV antibody were used; the assay used an antibody capture format. There was complete concordance between the results of saliva-based assays and those of serum-based assays, both of which were used for determining previous natural HAV exposure. However, for vaccine recipients, 100% concordance for saliva-based and serum-based assays occurred only at serum titers of > 9,000 mIU/mL, which were determined with use of the modified HAVAB assay. Saliva provides adequate sensitivity and specificity for determining naturally acquired HAV infection, although it is not useful in clinical trials for determining seroconversion after HAV vaccination.