The development of global vaccine stockpiles

Global vaccine stockpiles, in which vaccines are reserved for use when needed for emergencies or supply shortages, have effectively provided countries with the capacity for rapid response to emergency situations, such as outbreaks of yellow fever and meningococcal meningitis. The high cost and insufficient supply of many vaccines, including oral cholera vaccine and pandemic influenza vaccine, have prompted discussion on expansion of the use of vaccine stockpiles to address a wider range of emerging and re-emerging diseases. However, the decision to establish and maintain a vaccine stockpile is complex and must take account of disease and vaccine characteristics, stockpile management, funding, and ethical concerns, such as equity. Past experience with global vaccine stockpiles provide valuable information about the processes for their establishment and maintenance. In this Review we explored existing literature and stockpile data to discuss the lessons learned and to inform the development of future vaccine stockpiles.

Considerations for oral cholera vaccine use during outbreak after earthquake in Haiti, 2010-2011

Oral cholera vaccines (OCVs) have been recommended in cholera-endemic settings and preemptively during outbreaks and complex emergencies. However, experience and guidelines for reactive use after an outbreak has started are limited. In 2010, after over a century without epidemic cholera, an outbreak was reported in Haiti after an earthquake. As intensive nonvaccine cholera control measures were initiated, the feasibility of OCV use was considered. We reviewed OCV characteristics and recommendations for their use and assessed global vaccine availability and capacity to implement a vaccination campaign. Real-time modeling was conducted to estimate vaccine impact. Ultimately, cholera vaccination was not implemented because of limited vaccine availability, complex logistical and operational challenges of a multidose regimen, and obstacles to conducting a campaign in a setting with population displacement and civil unrest. Use of OCVs is an option for cholera control; guidelines for their appropriate use in epidemic and emergency settings are urgently needed.

Prevalence of and risk factors for antibody to hepatitis E virus seroreactivity among blood donors in Northern California

To evaluate antibody to hepatitis E virus (anti-HEV) seroreactivity, 5000 US blood donors were tested for anti-HEV by two EIAs: a mosaic protein assay (MPr-EIA) and a recombinant protein assay (RPr-EIA). Overall, 59 (1.2%) were seroreactive by MPr-EIA and 70 (1.4%) were seroreactive by RPr-EIA. The overall concordance between tests was 98.5% (4925/5000); the concordance among reactive sera by either test was only 27% (27/102). In a case-control study, seroreactive persons were more likely than seronegative persons to have traveled to countries in which HEV is endemic (odds ratio [OR] for MPr-EIA = 4.3, P < .001; OR for RPr-EIA = 2.5, P = .005), but 31% of MPr-EIA anti-HEV-reactive persons and 38% of RPr-EIA anti-HEV-reactive persons had no history of international travel. These findings suggest that travelers to regions in which HEV is endemic can acquire subclinical HEV infection. The significance of anti-HEV seroreactivity among persons without an international travel history needs to be determined.

Nosocomial transmission of hepatitis A in a pediatric hospital traced to an anti-hepatitis A virus-negative patient with immunodeficiency

From July through October 1991, an outbreak of hepatitis A virus (HAV) infection involving 26 hospital staff, inpatients and household contacts occurred in a pediatric hospital. All ill staff members had cared for one inpatient who had profuse diarrhea with gross fecal contamination of the environment, negative HAV serology and idiopathic immunodeficiency. HAV infection in this patient was later confirmed by polymerase chain reaction. Among hospital staff HAV attack rates were highest in nursing personnel (15%). A retrospective cohort study of nurses found that the risk of infection was greatest in those who handled the source patient's soiled bed pad (relative risk, 6.7; 95% confidence intervals, 1.6, 27.8), diaper (relative risk, 5.4; 95% confidence intervals, 0.8, 39.2) or gown (relative risk, 2.9; 95% confidence intervals, 1.1, 7.8). Glove use during these activities was not associated with a lower risk of infection, possibly because of gross environmental contamination or less use than reported. This situation was unusual because the patient was HAV-infected but had negative serology, probably because of immunodeficiency. In situations of potentially extensive environmental contamination, such as with a diapered or incontinent patient with suspected or confirmed hepatitis A, careful attention to frequent handwashing is an essential protective measure; in addition strict glove use whenever entering the patient's room should be followed to provide additional protection.

Prevention of hepatitis B virus infection

Hepatitis B virus infection is the most important cause of acute and chronic liver disease worldwide. The Immunization Practices Advisory Committee has proposed a comprehensive strategy to eliminate the transmission of hepatitis B virus in the United States. The three phases of this strategy are prevention of perinatal transmission of the hepatitis B virus, universal vaccination of all infants against hepatitis B virus infection and selected vaccination of high-risk adolescents and adults. Because family physicians provide obstetric, perinatal, adolescent and adult care, they can have a major influence on the success of this strategy.