Infectious Diseases News Brief - March 6, 2009

[Current Issue -Table of content]

Meningococcal C Vaccine Associated With Decreased Canadian Cases Of Most Deadly Strain Of Meningitis

Universal childhood vaccination against meningococcal C appears to reduce Canadian incidence of the most deadly strain of bacterial meningitis, reports new research published in the March issue of The Pediatric Infectious Disease Journal.  The Men C vaccine was introduced as part of universal immunization programs for children in Quebec and Alberta in 2002 and in British Columbia and Prince Edward Island in 2003.  By 2005, all Canadian provinces included Men C vaccine as part of routine childhood vaccinations. Staggered implementation across Canada offered researchers the opportunity to evaluate the universal vaccination program.  Prior to Men C universal vaccination, BC, Alberta, and Quebec had rates of meningococcal C disease that were nearly 4.5 times higher than the rest of Canada. The study reports that today these provinces have the lowest rates in Canada, from 0.41 cases per 100,000 people in 2002 down to 0.07 per 100,000 in 2006. The provinces with later introduction of universal Men C vaccination showed no major changes in the one year of follow up study, with annual rates of meningococcal C at 0.08 per 100,000 people in 2006.

Source: Medical News Today 3 March 2009
http://www.medicalnewstoday.com/articles/140947.php

HIV Rates Surprisingly High In The Over 50s

A new report suggests that HIV infection and prevalence rates are surprisingly high among older people, who seem to have been completely ignored by research and surveillance, perhaps because we don't assume they are at risk. However this also means that many cases of HIV among the over 50s go undiagnosed.  There is little data on how many people over the age of 50 are infected with HIV (ie prevalence), as this age group is rarely included in health surveys.  Data on HIV incidence rates among older people is also scarce (incidence is new cases per year whereas prevalence is how many people have a disease). While developing countries have limited case reporting systems, the authors wrote that as far as identifying HIV rates in older people, industrialized countries aren't much better. However, what data there is suggests incidence of HIV in older people is rising, mostly from information gathered in the US.  Much research shows that older people are less likely to practise safe sex compared to younger age groups, and there is some evidence from industrialized countries that use of erectile dysfunction drugs is linked to risky sexual behaviour, and there have been debates about whether men who are HIV-positive should be given these drugs.  However, the authors emphasized that while sexual activity was probably the most likely way, more research was needed to find out the relative risks of the different ways older people acquire HIV.  Older people diagnosed with HIV progress to AIDS much faster, and this could be partly because of age but also because they are not diagnosed as early as their younger counterparts, who are also more likely to be screened for the virus.

Source: Medical News Today 4 March 2009
http://www.medicalnewstoday.com/articles/141005.php

Measuring the Impact of Rotavirus Acute Gastroenteritis Episodes (MIRAGE): A prospective community-based study

Current assessments of the burden of rotavirus (RV)-related gastroenteritis are needed to evaluate the potential benefits of RV immunization interventions. The objective of the present study was to characterize the burden of RV gastroenteritis among children presenting in outpatient settings with gastroenteritis.  Between January and June 2005, 395 children younger than three years of age presenting with gastroenteritis symptoms (at least three watery or looser-than-normal stools, or forceful vomiting within the previous 24 h period) were recruited from 59 Canadian clinics and followed for two weeks. Stool specimens were tested for the RV antigen. Gastroenteritis-related symptoms, health care utilization, parental work loss and other cases of gastroenteritis in the household were assessed by questionnaires and daily symptom cards that were completed by caregivers.  Of 336 conclusive test results, 55.4% were RV positive (RV+). In addition to diarrhea, 67.2% and 89.3% of RV+ children experienced fever or vomiting, respectively. Compared with RVnegative (RV-) children, RV+ children were more likely to experience the three symptoms concurrently (57.0% versus 26.7%; P<0.001), to be hospitalized (12.9% versus 3.9%; P=0.008) and to induce parental work loss (53.8% versus 37.3%; P=0.003). The median duration of gastroenteritis was eight days for RV+ children (nine days for RV- children). Additional cases of gastroenteritis were present in 46.8% of households in the RV+ group (51.3% of households in the RV- group).  RV gastroenteritis cases were more severe than other gastroenteritis cases, were hospitalized more often and were associated with considerably more work loss.

Source: The Canadian Journal of Infectious Diseases and Medical Microbiology
November/December 2008, Volume 19 Issue 6: 397-404