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.

Flu Treatment in Small Children

Source: Heinonen S, et al. Early Oseltamivir treatment of influenza in children 1-3 years of age: A randomized controlled trial. Clin Infect Dis. 2010;51:887-894.

During the 2007-2008 and 2008-2009 influenza seasons, children ages 1-3 years, with influenza-like symptoms, were randomized to receive oseltamivir suspension vs. matching placebo for 5 days. Treatment was administered within 48 hours of onset of symptoms, and the study was double-blinded. The duration and severity of symptoms were recorded by parents in a daily log for 21 days.

A total of 408 children were randomized (203 to oseltamivir therapy). Ninety-eight children had laboratory-confirmed influenza, including 79 with influenza A and 19 with influenza B. Looking at children with influenza A who received the study drug within 24 hours of symptom onset, the median time to resolution of clinical symptoms was significantly shorter in the active treatment group compared with the placebo group (3.0 vs. 6.5 days). In those children who had not been vaccinated, the median time to resolution of symptoms also was shorter for those receiving active drug compared with those receiving placebo (3.4 vs. 7.3 days). Perhaps most importantly, parents of children receiving active therapy reported fewer missed days of work. As anticipated, no benefit of treatment was observed in children with influenza B infection.

Young children ages 1-3 years of age who receive prompt antiviral intervention for influenza A within 12-24 hours have a statistically significant reduction in the duration of symptoms by at least 3.5-4 days compared to untreated children.

Haiti Hit with Cholera

Source: Cholera outbreak — Haiti, October 2010. MMWR. 2010;59:1411; ProMED-mail posts November 11 and 12, 2010; www.promedmail.org

Cholera is rapidly hopscotching its way across Haiti. The first case occurred a mere 3 weeks ago, on October 20, and within 48 hours began spreading down the main coast highway to the slums on the outskirts of Port-au-Prince. By November 11, promedmail alerts reported that "all of the hospitals in Port-au-Prince are overflowing." By November 12, more than 12,000 people had become ill, with 796 reported dead. Cases are appearing in the tent cities outside of Port-au-Prince, where thousands are still left homeless from the January 2010 earthquake.

Cholera is not endemic in Haiti and, as a result, the entire population of 10 million people is non-immune and vulnerable to infection. The disease has spread quickly because of poor sanitation, lack of clean water, and crowded living conditions in slums and makeshift tent cities. There has been angry fingerpointing at Nepalese peacekeepers who accidentally imported the bacteria, which was confirmed by the CDC. DNA fingerprinting of isolates from 13 case patients in Haiti confirmed a match with a Southeast Asian strain of Cholera currently circulating in Nepal (where the disease is endemic). The serovar has been identified as toxigenic Vibrio cholerae 01, serotype Ogawa, biotype El Tor. Susceptibility testing demonstrates sensitivity to tetracycline, ciprofloxacin, and kanamycin, and resistance to trimpethoprim-sulfamethoxazole, sulfisoxazole, furazolidone, naladixic acid, and streptomycin.

Thus far, no U.S. travelers to Haiti have been affected. Updated information on the outbreak is being posted at http://www.cdc.gov/haiticholera.

In Favor of Mandatory Flu Vaccination of Health Care Workers

Source: Talbot TR, et al. Revised SHEA position paper: Influenza vaccination of healthcare personnel. Infection Control and Hospital Epidemiology. 2010;31:987-995.

Voluntary influenza vaccination rates of healthcare workers in the United States remain marginal, despite years of educational programs and lobbying in favor of vaccination. According to a 2009 RAND report, 53% of HCWs in the United States received influenza vaccine during the 2008-2009 influenza season. This figure was essentially unchanged last year, despite the heightened awareness of influenza morbidity and mortality associated with the H1N1 outbreak. At least 39% of HCWs surveyed reported no intention of receiving vaccine.

Two randomized clinical trials have demonstrated that vaccination of HCWs is a powerful and effective tool at reducing transmission of influenza and reducing patient mortality. The first, which was performed at 44 long-term healthcare facilities, involving more than 1,700 HCWs and 2,600 residents, demonstrated a significant reduction in influenza-like illness in both HCWs and residents. This benefit was observed even when residents of the facilities had been broadly vaccinated. A recent French study also demonstrated a reduction in resident morality among 40 facilities where HCWs had increased vaccination rates. Modeling studies suggest that a 100% vaccination rate of HCWs could result in a 43% reduction in influenza among hospitalized patients and a 60% reduction in nursing home residents.

Despite these figures, many HCWs remain entrenched in their disinterest or refusal to receive flu vaccine, the basis for which is not entirely clear. Informal surveys reveal a perception of a lack of vaccine efficacy (somewhat true), fear of vaccination, especially with the "new" H1N1 vaccine (which may have something to do with the government's insistence on referring to this strain of influenza as "novel"), and a sustained concern that you can "catch the flu from the vaccine." Perceived government mismanagement of the vaccine program in past years and problems with vaccine manufacturing facilities contribute to a distrust of the government's intent and of the vaccine itself.

There also is an expressed anxiety about the government's intrusion in what should be an "individual choice." And yet most of these same HCWs willingly submit to mandatory screening and vaccination for other communicable diseases in the workplace, including measles, mumps, rubella, varicella, HBV, and — now in California — Tdap. For many of us, evidence of immunity to these infections is a mandatory condition of employment.

For this reason, several states and health-care organizations have initiated different types of programs to encourage or enforce vaccination. These types of programs fall into four broad categories, as follows:

1) Mandatory vaccine of all HCWs, with defined medical and religious exemptions. Some allow exemption for "personal beliefs." Such programs were able to achieve vaccine rates of 95%-98% during the 2009-2010 influenza season.

2) Another approach is to maintain programs for voluntary vaccination but mandate that employees who "opt out" must wear a mask while performing clinical activities. Whether a daily reminder of potential risk, or the sheer annoyance, this approach may result in improved vaccine rates. A German study demonstrated that employee vaccine rates increased from 33% to 58% within 10 days of implementing this requirement.

3) Strategies that use influenza vaccine as a Quality Indicator, with disclosure of the information to the public, also have been found to improve vaccine rates. In a group of 115 acute care hospitals in Iowa, voluntary vaccine rates improved to 82% with such a program.

4) A simple approach to encouraging vaccination is the use of a signed declination statement for those who refuse vaccination. In our local clinic and hospital, this approach boosted vaccine rates from approximately 52% to 65%-72%. Anecdotally, educational tools to promote vaccination, including Internet modules designed to reassure and encourage vaccination, have not been effective.

So, how do we encourage flu vaccination of HCWs in the United States? You don't — it should be mandatory, just like evidence of adequate immunity to other communicable diseases is necessary. This is not a question of personnel freedom. HCWs have an obligation to promote the health and safety of their patients — and should receive annual influenza vaccine as a condition of their employment.

HIV Transmission During Pregnancy

Source: Tubiana R. et al. Factors associated with mother-to-child transmission of HIV-1 despite a maternal viral load < 500 copies/mL at delivery: A case-control study nested in the French Perinatal Cohort (EPF-ANRS C01). Clin Infect Dis. 2010; 50:585-96.

Rates of mother-to-child transmission (MCT) are estimated to be as low as 0.5% to 1.5% in moms receiving antiretroviral therapy with undetectable HIV-1 viral loads at the time of delivery. And yet, this small risk was calculated to be a factor in the transmission of HIV to at least 20% of the children perinatally infected in a large cohort of mother-child pairs in France. From 1997 to 2006, mother-child pairs have been tracked as part of a large perinatal project in France, which includes 7,425 mother-infant pairs. The overall rate of MCT in this large group is 1.5% (115 pairs).

In order to determine the risks for maternal transmission of HIV in women who had undetectable viral loads at the time of delivery, a subset of maternal-child pairs, defined as follows, were examined: the woman had to have received antiretroviral therapy during her pregnancy, the last HIV viral load before or at delivery was < 500 copies/mL, the gestational age of the child had to be at least 37 weeks, and there was no evidence of breast-feeding. A total of 4,281 mother-child pairs met the criteria. Risk factors for transmission in this group were examined, resulting in a comparison of 19 mother-baby pairs with HIV+ babies and 60 control pairs.

Control-case mothers were more likely to be receiving antiretroviral therapy at the time of conception compared to case patients (45% vs. 16%, p = .017). In addition, significantly more control mothers had undetectable viral loads at 14 and 30 weeks of pregnancy. At 14 weeks, 38% of control mothers vs. 0% of case mothers had undetectable viral loads < 500 copies/mL (p = .02). During pregnancy, median viral loads also were significantly higher for case patients than controls, and peak viral loads during pregnancy > 10,000 copies/mL occurred in 63% of case patients vs. 36% of control pairs. The HIV viral load also appeared to decrease more slowly in mothers treated with antiretroviral therapy. Multivariate analysis demonstrated that the only independent risk factor for maternal-child transmission in this group was the viral load at 30 weeks +/- 4 weeks of pregnancy.

A lower proportion of case patients compared with controls had VLs < 50 copies/mL at delivery, but this figure did not reach significance.

Early and sustained control of HIV viremia is essential in reducing transmission of HIV during pregnancy. These data suggest that mothers who receive ART throughout their pregnancy, including at the time of conception, have the lowest rates of transmission (which may prompt a re-examination of the current guidelines). Nonetheless, the rate of MCT for mothers with VLs < 50 at the time of delivery was 0.4%, indicating that transmission can occur even in mothers with excellent virologic suppression during their pregnancies.