Updates by Carol Kemper, MD, FACP
Updates
By Carol A. Kemper, MD, FACP, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center, Section Editor, Updates; Section Editor, HIV, is Associate Editor for Infectious Disease Alert.
Meningococcal Vaccine Reminder
A reminder: meningococcal vaccine. Med Lett Drugs Ther. 2008;50:57.
As kids prepare for school this fall, remember that the United States American College of Immunization Practices (ACIP) recommends administration of meningococcal vaccine to previously unvaccinated children starting high school or going off to college. As of 2007, kids ages 11-18 years may receive a single dose of the quadrivalent conjugated polysaccharide meningococcal vaccine (Menactra, Sanofi Pasteur). The conjugate vaccine is preferred over the capsular polysaccharide vaccine (Menommune, also by Sanofi Pasteur) because of its enhanced immunogenicity.
Freshmen planning on living in dorms or dormitory-like settings (eg, group homes, fraternities) and kids starting high school are priority groups.
Malaria in Children of Immigrants
Mascarello M, et al. Imported malaria in adults and children: epidemiologic and clinical characteristics of 380 consecutive cases observed in Verona, Italy. J Trav Med. 2008;15:229-236.
Several of us on the board of Infectious Disease Alert live in an area rich in immigrants. It is estimated that 40% of the Silicon Valley workforce are immigrants, about 70% of whom are from India. This provides us specialists in infectious diseases more than the usual number of cases of endemic disease such as TB, malaria, and typhoid fever. This experience is not limited to the adult working population in our area; in my experience, immigrant parents do not think twice about taking their children home to their country of origin to visit family and friends. Just this week, I was consulting on a case of a young woman with TB lymphadenitis, who had just returned from Mumbai, India, this spring with her 2- and 4-year-old children. Another woman with FUO and skin test conversion informed me she was planning to take her 3-month-old and 2-year-old to India in October for one month. All of these children were born in the United States and had never previously stepped foot in India.
It is now estimated that half of the cases of hepatitis A in the United States are occurring in the children of immigrants who return to their country of origin with kids with their non-immune children.
Mascarello et al examined 43 cases of malaria in children admitted to hospitals in northern Italy from 2000-2004. All affected children were born to immigrant families; no case of malaria occurred in an Italian child. Nearly half (47%) of the children were born in endemic areas who had come to Italy with their parents for purposes of immigration. The other half (53%) were born in Italy (hence, were non-immune) and traveled back to their parents' country to visit relatives and friends. The mean age of the children was 9-years-old; five (12%) were under the age of 5-years-old. Mascarello et al divided these two groups into those who were presumably immune to malaria and those who were non-immune. All of the children required hospitalization. Forty-one of the 43 cases (95%) were due to P. falciparum; the remaining two cases were due to P. vivax. Forty-one of 43 (95%) had traveled to Africa; the remaining two cases had traveled to Asia. There were clear differences between the two groups. Eight of the cases were considered severe or life-threatening, as defined by WHO criteria; severe cases occurred in 30% of those who were non-immune compared with 5% of those immune. The mean age of these eight children was 3.1-years-old. Higher parasite loads, longer times to clearance of parasitemia, lower platelet counts, and duration of fever were statistically more significant in the non-immune group compared with children with immunity.
Obtaining a good travel history is essential to caring for the ill children of immigrants. Pediatricians should, however, anticipate that children of immigrants may travel and are at risk for travel-related diseases, a risk their patients may underestimate or fail to consider. Clinicians should provide travel-related and vaccine advice to such parents before travel occurs.
HIV Screening in an Acute Care Setting
Walensky RP, et al. Revising expectations from rapid HIV tests in the emergency department. Ann Intern Med. 2008;149:153-160; Pilcher CD, Hare CB. The deadliest catch: fishing for HIV in new waters. Ann Intern Med. 2008;149:204-205.
Per current USPHS guidelines, we recently implemented rapid HIV screening for all parturient women presenting to Labor and Delivery lacking prior HIV test results, or at high risk for HIV during pregnancy. Our hospital sees nearly 4,000 deliveries per year, and while at least theoretically, most if not all of these women should have been screened for HIV as part of their pre-natal care, many are not, possibly because of the low prevalence of HIV in our area.
Which puts the hospital in the difficult position of having to provide rapid HIV screening in an acute care setting — the delivery room. Based on estimates of the low prevalence of HIV in our area, and the reported sensitivity and specificity of the rapid HIV test (> 99%), we estimated 4-10 false-positives for every true positive. This means that a number of young woman and infants will receive peripartum HIV drugs unnecessarily, not to mention the psychological distress, counseling, and time and effort.
Walensky et al at Brigham experienced similar difficulties when implementing rapid HIV testing in an ER setting. Although again, worthy in theory, they found that the specificity of the screening test was lower than expected, yielding more false-positives than anticipated, creating additional complexities at work for ER physicians and staff.
A total of 849 adults presenting to Brigham and Women's Hospital ER in Boston in 2007 were screened using the OraQuick Advance Rapid HIV-1/2 antibody test (Orasure Technologies, Bethlehem, Pennsylvania). Patients with a positive test were offered counseling and confirmatory testing using a panel of ELISA, Western Blot, and plasma HIV RNA PCR. Eligible patients were 18-75 years of age, had intermediate illness (neither too ill to participate or too well to be in the ER long enough), not knowingly HIV+, and not receiving prenatal care.
Thirty-nine (4.6%) of 849 tested had a positive test result (another 544 eligible patients were not tested, either because they declined, they were not in the ER sufficiently long, or the staff were too busy). Eight of the 39 women (21%!) declined confirmatory testing. Of the remaining 31, five (16%) were true-positives. Thirteen (50%) had indeterminate Western Blots, and 25 (96%) had negative PCRs; the remaining patient had a viral load of 86 on an initial PCR test, but tested negative two weeks later.
Based on these figures, the prevalence of confirmed HIV in this acute ER population was 0.6%. The specificity of the rapid test was 96.9%, and it provided a false-positive rate of 3.1% — more than 15 times higher than anticipated. Walensky et al advised against the use of the Western Blot alone for confirmation, as it would have mistakenly suggested many more possible early infections, prompting further testing, and instead recommend the use of the confirmatory panel, including plasma viral load.
Interestingly, Walensky et al report that the first two false-positive results prompted temporary closure of the study, pending further investigation and a laboratory audit by the Department of Public Health and the manufacturer, looking for irregularities in procedures. The audit uncovered no flaws, and the study was resumed once the informed consent form was modified to restate the accuracy of the rapid test. Despite these difficulties and their results, Walensky et al believe support for the rapid screening remains high. They comment that for every 100 patients tested in the ER at their institution, 95 leave knowing they are negative, and five leave pending confirmation. One of these will prove HIV-positive, and the other four will be generally informed of their negative status "within 24 hours."
These studies leave open several questions: the cost of the added confirmatory testing and counseling in many more pts than anticipated in an acute care setting, the imposition on busy ER personnel, and what happened to the 40% of people who either were never tested or declined testing, or those eight who refused confirmatory testing. In my experience, patients with risk factors, or those who suspect they may be positive, are often the most reluctant to be tested. In addition, these figures fall apart, to some degree, if testing is shifted to an area with a lower prevalence of HIV — while Walensky et al may accept a ratio of 4:1 false-positives to true-positives in their ER setting, an HIV prevalence of 1 in 1000 would yield a false-positive to true-positive ratio of 24:1. Although not feasible in the delivery room, at what point does it make sense to use more specific tests (but not rapid) for screening purposes in the ER?
TB Linked to IMF Loan Funding
ProMED-mail post, July 22, 2008; www.promedmail.org
The increase in tuberculosis in Russia and the former Soviet Eastern Bloc countries has been blamed on the downfall of the Soviet Union in the early 1990s. These authors provide an alternate and intriguing explanation. Investigators from the University of Cambridge examined TB data from 21 countries in central and Eastern Europe from 1989 forward. The premise was that International Monetary Fund loans to countries are often pegged to reductions in government spending, which all too often results in reductions in health care dollars. The IMF specifically grants loans in stages based on spending performance targets, putting pressure on governments to comply.
The investigators found increased rates of TB and increased rates of death from TB in countries receiving funding from the IMF. Despite declining rates of TB in several of these countries prior to receiving loans, cases of TB increased 13% and death rates from TB rose by 16% in countries receiving IMF loans, compared with countries not participating in IMF programs. Increased rates were associated with larger loans and a longer duration of participation in the loan program; for every year the country participated, death rates rose by another 4%. Specifically, researchers observed that the timing of the IMF program was associated with lower government spending on TB programs, and fewer persons receiving therapy through directly observed treatment (DOT).
This is an example of how national — or in this case, international — policy can have serious and unintended consequences for health care.
As kids prepare for school this fall, remember that the United States American College of Immunization Practices (ACIP) recommends administration of meningococcal vaccine to previously unvaccinated children starting high school or going off to college.Subscribe Now for Access
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