Alison F. Hinckley

Adverse event reports following yellow fever vaccination.

Yellow fever (YF) vaccine has been used for prevention of YF since 1937 with over 500 million doses administered. However, rare reports of severe adverse events following vaccination have raised concerns about the vaccines safety. We reviewed reports of adverse events following YF vaccination reported to the U.S. Vaccine Adverse Event Reporting System (VAERS) from 2000 to 2006. We used estimates of age and sex distribution of administered doses obtained from a 2006 survey of authorized vaccine providers to calculate age- and sex-specific reporting rates of all serious adverse events (SAE), anaphylaxis, YF vaccine-associated neurotropic disease, and YF vaccine-associated viscerotropic disease. Reporting rates of SAEs were substantially higher in males and in persons aged > or =60 years. These findings reinforce the generally acceptable safety profile of YF vaccine, but highlight the importance of physician and traveler education regarding the risks and benefits of YF vaccination, particularly for travelers > or =60 years of age. Vaccination should be limited to persons traveling to areas where the risk of YF is expected to exceed the risk of serious adverse events after vaccination, or if not medically contraindicated, where national regulations require proof of vaccination to prevent introduction of YF.

Lyme Disease Testing by Large Commercial Laboratories in the United States

BACKGROUND Laboratory testing is helpful when evaluating patients with suspected Lyme disease (LD). A 2-tiered antibody testing approach is recommended, but single-tier and nonvalidated tests are also used. We conducted a survey of large commercial laboratories in the United States to assess laboratory practices. We used these data to estimate the cost of testing and number of infections among patients from whom specimens were submitted. METHODS Large commercial laboratories were asked to report the type and volume of testing conducted nationwide in 2008, as well as the percentage of positive tests for 4 LD-endemic states. The total direct cost of testing was calculated for each test type. These data and test-specific performance parameters available in published literature were used to estimate the number of infections among source patients. RESULTS Seven participating laboratories performed approximately 3.4 million LD tests on approximately 2.4 million specimens nationwide at an estimated cost of

Incidence of Clinician-Diagnosed Lyme Disease, United States, 2005-2010.

492 million. Two-tiered testing accounted for at least 62% of assays performed; alternative testing accounted for <3% of assays. The estimated frequency of infection among patients from whom specimens were submitted ranged from 10% to 18.5%. Applied to the total numbers of specimens, this yielded an estimated 240 000 to 444 000 infected source patients in 2008. DISCUSSION LD testing is common and costly, with most testing in accordance with diagnostic recommendations. These results highlight the importance of considering clinical and exposure history when interpreting laboratory results for diagnostic and surveillance purposes.

Birth Outcomes Following West Nile Virus Infection of Pregnant Women in the United States: 2003-2004

Extrapolation from a large medical claims database suggests that 329,000 cases occur annually.

Transmission of West Nile Virus Through Human Breast Milk Seems to Be Rare

BACKGROUND. Congenital West Nile virus (WNV) infection was first described in a single case in 2002. The proportion of maternal WNV infections resulting in congenital infection and clinical consequences of such infections are unknown. METHODS. In 2003 and 2004, women in the United States who acquired WNV infection during pregnancy were reported to the Centers for Disease Control and Prevention by state health departments. Data on pregnancy outcomes were collected. One of the maternal WNV infections was identified retrospectively after the infant was born. Maternal sera, placenta, umbilical cord tissue, and cord serum were tested for WNV infection by using serologic assays and reverse-transcription polymerase chain reaction. Infant health was assessed at delivery and through 12 months of age. RESULTS. Seventy-seven women infected with WNV during pregnancy were clinically followed in 16 states. A total of 71 women delivered 72 live infants; 4 women had miscarriages, and 2 had elective abortions. Of the 72 live infants, 67 were born at term, and 4 were preterm; gestational age was unknown for 1. Of 55 live infants from whom cord serum was available, 54 tested negative for anti-WNV IgM. One infant born with umbilical hernia and skin tags had anti-WNV IgM in cord serum but not in peripheral serum at age 1 month. An infant who had no anti-WNV IgM in cord blood, but whose mother had WNV illness 6 days prepartum, developed WNV meningitis at age 10 days. Another infant, whose mother had acute WNV illness at delivery, was born with a rash and coarctation of the aorta and had anti-WNV IgM in serum at 1 month of age; cord serum was not available. A fourth infant, whose mother had onset of WNV illness 3 weeks prepartum that was not diagnosed until after delivery, had WNV encephalitis and underlying lissencephaly detected at age 17 days and subsequently died; cord serum was not available. The following major malformations were noted among live-born infants: aortic coarctation (n = 1); cleft palate (n = 1); Down syndrome (n = 1); lissencephaly (n = 1); microcephaly (n = 2); and polydactyly (n = 1). One infant had glycogen storage disease type 1. Abnormal growth was noted in 8 infants. CONCLUSIONS. Of 72 infants followed to date in 2003 and 2004, almost all seemed normal, and none had conclusive laboratory evidence of congenital WNV infection. Three infants had WNV infection that could have been congenitally acquired. Seven infants had major malformations, but only 3 of these had defects that could have been caused by maternal WNV infection based on the timing of the infections and the sensitive developmental period for the specific malformations, and none had any conclusive evidence of WNV etiology. However, the sensitivity and specificity of IgM testing of cord blood to detect congenital WNV infection are currently unknown, and congenital WNV infection among newborns with IgM-negative serology cannot be ruled out. Prospective studies comparing pregnancy outcomes of WNV-infected and -uninfected women are needed to better define the outcomes of WNV infection during pregnancy.

West Nile Virus Infection Among Pregnant Women in a Northern Colorado Community, 2003 to 2004

INTRODUCTION.In September 2002, possible transmission of West Nile virus via human milk was reported for the first time. METHODS.Since 2003, the Centers for Disease Control and Prevention collected reports of maternal or infant West Nile virus illness during the breastfeeding period. All of the reported instances were reviewed. In addition, milk samples from women infected during pregnancy were tested for West Nile virus RNA and West Nile virus–specific antibodies. RESULTS.Six infants were reported to have breastfed from mothers with West Nile virus fever. Five of the 6 infants had no illness or detectable antibodies to West Nile virus in serum after onset of maternal illness. One infant who was not tested and developed a rash was otherwise well 1 week after onset of maternal illness. In addition, 2 infants were reported to have developed West Nile virus illness while breastfeeding; preceding maternal illness was not documented. Two breastfed infants whose mothers acquired West Nile virus fever in the last week of pregnancy developed West Nile virus–specific antibodies; both infant infections could have been congenitally acquired. Of 45 milk samples from women infected with West Nile virus during pregnancy, 2 had West Nile virus RNA, and 14 had immunoglobin M antibodies to West Nile virus. CONCLUSIONS.Of 10 reported instances since 2003 of maternal or infant West Nile virus illness while breastfeeding, transmission of West Nile virus through human milk could neither be ruled out nor confirmed for 5 cases; in 5 others, serologic tests indicated no vertical transmission. Transmission of West Nile virus through breastfeeding seems to be rare, but more information is needed.

Epidemiology of Human Plague in the United States, 1900–2012

OBJECTIVE. Since West Nile virus (WNV) was first detected in New York in 1999, it has spread across North America and become a major public health concern. In 2002, the first documented case of intrauterine WNV infection was reported, involving an infant with severe brain abnormalities. To determine the frequencies of WNV infections during pregnancy and of intrauterine WNV infections, we measured WNV-specific antibodies in cord blood from infant deliveries after a community-wide epidemic of WNV disease. METHODS. Five hundred sixty-six pregnant women who presented to Poudre Valley Hospital (Fort Collins, CO) for delivery between September 2003 and May 2004 provided demographic and health history data through self-administered questionnaires and hospital admission records. Umbilical cord blood was collected from 549 infants and screened for WNV-specific IgM and IgG antibodies with enzyme-linked immunosorbent assays, with confirmation by plaque-reduction neutralization tests. Newborn growth parameters, Apgar scores, and hearing test results were recorded. RESULTS. Four percent (95% confidence interval: 2.4–5.7%) of cord blood samples tested positive for WNV-specific IgG antibodies. No cord blood samples were positive for WNV-specific IgM antibodies. There were no significant differences between infants of seropositive and seronegative mothers with respect to any of the growth parameters or outcomes measured. CONCLUSIONS. Intrauterine WNV infections seemed to be infrequent. In our study, WNV infection during pregnancy did not seem to affect adversely infant health at birth. Larger prospective studies are necessary to measure more completely the effects of maternal WNV infection on pregnancy and infant health outcomes.

Effectiveness of Residential Acaricides to Prevent Lyme and Other Tick-borne Diseases in Humans

Epidemiologic changes reflect shifts in the populations at risk, the advent of effective therapy, and improved detection methods.

Surveillance for Lyme Disease — United States, 2008–2015

BACKGROUND In the northeastern United States, tick-borne diseases are a major public health concern. In controlled studies, a single springtime application of acaricide has been shown to kill 68%-100% of ticks. Although public health authorities recommend use of acaricides to control tick populations in yards, the effectiveness of these pesticides to prevent tick bites or human tick-borne diseases is unknown. METHODS We conducted a 2-year, randomized, double-blinded, placebo-controlled trial among 2727 households in 3 northeastern states. Households received a single springtime barrier application of bifenthrin or water according to recommended practices. Tick drags were conducted 3-4 weeks after treatment on 10% of properties. Information on human-tick encounters and tick-borne diseases was collected through monthly surveys; reports of illness were validated by medical record review. RESULTS Although the abundance of questing ticks was significantly lower (63%) on acaricide-treated properties, there was no difference between treatment groups in human-tick encounters, self-reported tick-borne diseases, or medical-record-validated tick-borne diseases. CONCLUSIONS Used as recommended, acaricide barrier sprays do not significantly reduce the household risk of tick exposure or incidence of tick-borne disease. Measures for preventing tick-borne diseases should be evaluated against human outcomes to confirm effectiveness.

TickNET—A Collaborative Public Health Approach to Tickborne Disease Surveillance and Research

PROBLEM/CONDITION Lyme disease is the most commonly reported vectorborne disease in the United States but is geographically focal. The majority of Lyme disease cases occur in the Northeast, mid-Atlantic, and upper Midwest regions. Lyme disease can cause varied clinical manifestations, including erythema migrans, arthritis, facial palsy, and carditis. Lyme disease occurs most commonly among children and older adults, with a slight predominance among males. REPORTING PERIOD 2008-2015. DESCRIPTION OF SYSTEM Lyme disease has been a nationally notifiable condition in the United States since 1991. Possible Lyme disease cases are reported to local and state health departments by clinicians and laboratories. Health department staff conduct case investigations to classify cases according to the national surveillance case definition. Those that qualify as confirmed or probable cases of Lyme disease are reported to CDC through the National Notifiable Diseases Surveillance System. States with an average annual incidence during this reporting period of ≥10 confirmed Lyme disease cases per 100,000 population were classified as high incidence. States that share a border with those states or that are located between areas of high incidence were classified as neighboring states. All other states were classified as low incidence. RESULTS During 2008-2015, a total of 275,589 cases of Lyme disease were reported to CDC (208,834 confirmed and 66,755 probable). Although most cases continue to be reported from states with high incidence in the Northeast, mid-Atlantic, and upper Midwest regions, case counts in most of these states have remained stable or decreased during the reporting period. In contrast, case counts have increased in states that neighbor those with high incidence. Overall, demographic characteristics associated with confirmed cases were similar to those described previously, with a slight predominance among males and a bimodal age distribution with peaks among young children and older adults. Yet, among the subset of cases reported from states with low incidence, infection occurred more commonly among females and older adults. In addition, probable cases occurred more commonly among females and with a higher modal age than confirmed cases. INTERPRETATION Lyme disease continues to be the most commonly reported vectorborne disease in the United States. Although concentrated in historically high-incidence areas, the geographic distribution is expanding into neighboring states. The trend of stable to decreasing case counts in many states with high incidence could be a result of multiple factors, including actual stabilization of disease incidence or artifact due to modifications in reporting practices employed by some states to curtail the resource burden associated with Lyme disease surveillance. PUBLIC HEALTH ACTION This report highlights the continuing public health challenge of Lyme disease in states with high incidence and demonstrates its emergence in neighboring states that previously experienced few cases. Educational efforts should be directed accordingly to facilitate prevention, early diagnosis, and appropriate treatment. As Lyme disease emerges in neighboring states, clinical suspicion of Lyme disease in a patient should be based on local experience rather than incidence cutoffs used for surveillance purposes. A diagnosis of Lyme disease should be considered in patients with compatible clinical signs and a history of potential exposure to infected ticks, not only in states with high incidence but also in areas where Lyme disease is known to be emerging. These findings underscore the ongoing need to implement personal prevention practices routinely (e.g., application of insect repellent and inspection for and removal of ticks) and to develop other effective interventions.