Biomedical subjects

R C Holman

Publications and source records attributed to R C Holman.

At least 55 records · Page 3Linked to original sources

PubMed1998

Progressive multifocal leukoencephalopathy in the United States, 1979-1994: increased mortality associated with HIV infection.

To examine trends in progressive multifocal leukoencephalopathy (PML) mortality in the United States, we analyzed PML death rates and deaths for 1979 through 1994, using US multiple cause-of-death data. During the 16-year study period 3,894 PML deaths were reported. The age-adjusted death rate increased more than 20-fold, from less than 0.2 per million persons before 1984 to 3.3 per million persons in 1994. The increase was attributable to infection with human immunodeficiency virus (HIV) which was recorded on 2,267 (89.0%) of 2.546 death records from 1991 through 1994. PML age-adjusted death rates increased abruptly for all males beginning in 1984 and for black females in 1990. Only a small increase was observed for white females. In 1994, PML was reported in 2.1% of white males who died with HIV-associated disease compared with 1.2% of white females and 1.0% of black males and females who died of similar causes. The epidemic of PML deaths is increasing in parallel with the AIDS epidemic. The increase in HIV-associated PML deaths, first noted among males, has also become apparent among females and probably reflects the increasing importance of drug use and heterosexual transmission of HIV. The reason for the higher prevalence of PML among white males with HIV infection is unknown.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Decline in sepsis-associated neonatal and infant deaths in the United States, 1979 through 1994.

BACKGROUND: Infant mortality in the United States has continued to decline in recent years, but changes in sepsis-associated deaths among infants have not been evaluated previously. METHODS: Data from US death records were analyzed for the period 1979 through 1994 to assess trends in sepsis-associated deaths among newborns and older infants. RESULTS: Annual neonatal mortality associated with sepsis declined by 25% from 50.5 deaths per 100 000 live births in 1979 through 1981 to 38.0 deaths per 100 000 live births in 1992 through 1994. Although infant mortality associated with sepsis declined from 71.7 to 56.4 per 100 000 live births over the same period, this decline was attributable to lower sepsis-related mortality among newborns. The rates of sepsis-associated deaths declined for both preterm and term deliveries. Approximately 2260 infants (1521 of whom were newborns) died of sepsis per year in 1992 through 1994. Sepsis-associated death was more likely to occur among infants who were male, black, preterm, or born in the South. Among black infants, the racial gap in sepsis-associated mortality was greater for term than for preterm infants. CONCLUSIONS: Despite declines in the overall sepsis-related mortality among newborns, racial and regional gaps in mortality persisted over the 16-year study period. Almost half of the sepsis-related deaths occurred among infants who were born prematurely. Disproportionate rates of prematurity among blacks and infants born in the South may have contributed to persistently high sepsis-related mortality in these groups. Future efforts to reduce the incidence of sepsis-associated deaths will depend on targeting higher risk populations and reducing prematurity.

Age Distribution↗

PubMed1997

Pediatric hospitalizations for croup (laryngotracheobronchitis): biennial increases associated with human parainfluenza virus 1 epidemics.

Croup is a common manifestation of respiratory tract infection in children, and human parainfluenza virus 1 (HPIV-1) is the agent most commonly associated with croup. In the United States, HPIV-1 produces a distinctive pattern of biennial epidemics of respiratory illness during the autumn months of odd-numbered years. National Hospital Discharge Survey data for croup hospitalizations among patients <15 years old between 1979 and 1993 were examined along with laboratory-based surveillance data on HPIV-1 activity in the United States. The mean annual number of croup hospitalizations was 41,000 (range, 27,000-62,000/year). Ninety-one percent of hospitalizations occurred among children <5 years of age. Minor peaks in croup hospitalizations occurred each year in February, and major peaks occurred in October of odd-numbered years, coincident with peak HPIV-1 activity. Each biennial epidemic of HPIV-1 was associated with 18,000 excess croup hospitalizations nationwide.

Adenovirus Infections, Human↗

PubMed1997

Visualizing geographic and temporal trends in rotavirus activity in the United States, 1991 to 1996. National Respiratory and Enteric Virus Surveillance System Collaborating Laboratories.

BACKGROUND: Rotavirus is the leading cause of severe pediatric gastroenteritis worldwide. A vaccine may soon be licensed for use in the United States to prevent this disease. To characterize US geographic and temporal trends in rotavirus activity, we made contour maps showing the timing of peak rotavirus activity. METHODS: From July, 1991, through June, 1996, 79 laboratories participating in the National Respiratory and Enteric Virus Surveillance System reported on a weekly basis the number of stool specimens that tested positive for rotavirus. The peak weeks in rotavirus detections from each laboratory were mapped using kriging, a modeling technique originally developed for geostatistics. RESULTS: During the 5-year period 118,716 fecal specimens were examined, of which 27,616 (23%) were positive for rotavirus. Timing of rotavirus activity varied by geographic location in a characteristic pattern in which peak activity occurred first in the Southwest from October through December and last in the Northeast in April or May. The Northwest exhibited considerable year-to-year variability (range, December to May) in the timing of peak activity, whereas the temporal pattern in the remainder of the contiguous 48 states was relatively constant. CONCLUSION: Kriging is a useful method for visualizing geographic and temporal trends in rotavirus activity in the United States. This analysis confirmed trends reported in previous years, and it also identified unexpected variability in the timing of peak rotavirus activity in the Northwest. The causes of the seasonal differences in rotavirus activity by region are unknown. Tracking of laboratory detections of rotavirus may provide an effective surveillance tool to assess the impact of a rotavirus vaccination campaign in the United States.

Humans↗

PubMed1997

The epidemiology of necrotizing enterocolitis infant mortality in the United States.

OBJECTIVES: This study examined trends and risk factors for infant mortality associated with necrotizing enterocolitis in the United States. METHODS: Necrotizing enterocolitis-associated deaths and infant mortality rates from 1979 through 1992 were determined by means of US multiple cause-of-death and linked birth/infant death data. RESULTS: Annual necrotizing enterocolitis infant mortality rates decreased from 1979 through 1986 but increased thereafter and were lower during the 3-year period before (1983 through 1985;11.5 per 100,000 live births) the introduction of surfactants than after (1990 through 1992; 12.3 per 100,000). Low-birthweight singleton infants who were Black male, or born to mothers younger than 17 had increased risk for necrotizing enterocolitis-associated death. CONCLUSIONS: As mortality among low-birth weight infants continues to decline and smaller newborns survive early causes of death, necrotizing enterocolitis-associated infant mortality may increase.

Age Distribution↗

PubMed1996

Utility of emergency, telephone-based national surveillance for Hantavirus pulmonary syndrome. Hantavirus Task Force.

On May 27, 1993, in response to the outbreak investigation of newly recognized Hantavirus pulmonary syndrome (HPS) in the Four Corners states (New Mexico, Arizona, Utah, and Colorado), the Centers for Disease Control and Prevention established a national surveillance case definition for severe, unexplained respiratory disease to determine the extent of HPS throughout the United States. A toll-free telephone hotline number was instituted to provide updated information about unexplained respiratory illness and to serve as a passive mechanism for reporting suspected cases. Clinical information was obtained from callers reporting suspected cases, and diagnostic specimens and medical record reviews were requested from health care providers. From June 3 through December 31, 1993, the hotline received 21,443 telephone inquiries; callers identified 280 suspected cases living outside the Four Corners states with at least one specimen available for diagnostic testing. By December 31, 1993, 21 confirmed cases (age range, 14 to 58 years) residing in 11 states outside the Four Corners region had been identified. This passive surveillance system was successful in rapidly identifying the widespread sporadic geographic distribution for HPS cases throughout the United States and could serve as a model for similar emergencies. Expanding and coordinating surveillance systems for the early detection, tracking, and evaluation of emerging infections is a critical component of disease prevention.

Disease Outbreaks↗

PubMed1996

Outbreak of vertigo in Wyoming: possible role of an enterovirus infection.

An epidemiologic investigation was conducted to characterize and evaluate the possibility of a viral aetiology of an outbreak of acute vertigo in Hot Springs Country, Wyoming, during autumn 1992. Case-finding identified Hot Springs County residents who sought medical attention for new onset vertigo during 1 August, 1992-31 January 1993. Thirty-five case-patients and 61 matched controls were interviewed and serum specimens were obtained during January 1993. Case-patients were more likely than controls to report symptoms (e.g. fatigue, sore throat, fever, diarrhoea) of antecedent acute illness. Case-patients did not have a significantly greater prevalence or mean titre of IgG antibodies to respiratory syncytial virus, parainfluenza viruses, Epstein-Barr virus, and cytomegalovirus than controls. Serologic evidence of recent enterovirus infection (IgM antibodies) was found for 74% of case-patients compared with 54% of controls (P < 0.05), suggesting a possible association between vertigo and enterovirus infection. Future studies are needed to define the role of enteroviruses in innerear diseases.

Adolescent↗

PubMed1996

Hantavirus pulmonary syndrome: the first 100 US cases.

In the spring of 1993, hantavirus pulmonary syndrome (HPS) "emerged" in the southwestern United States, where a multiagency investigation led to the rapid description of this new clinical entity and its etiology. Analysis of the first 100 US cases identified showed that the disease was distributed in 21 states, had gone unrecognized since at least 1959, and had a distinct spring-early summer seasonality. Of the infected persons, 54% were male; 63% were Caucasian, 35% were Native American, and 2% were African American. The average age of case-patients was 34.9 years, and 8 were children or adolescents aged < or = 16 years. The overall case-fatality rate was 52%. There was a 91% concordance among serologic, immunohistochemical, and molecular results. HPS in the United States is caused by at least three newly described pathogenic hantaviruses, each of which has a distinct rodent host, and cases of HPS have been recently recognized in Canada and South America. National surveillance of this sporadic disease remains essential for further defining the epidemiology and clinical spectrum.

Adolescent↗

PubMed1996

The epidemiology of rotavirus diarrhea in the United States: surveillance and estimates of disease burden.

The decision to develop rotavirus vaccines was predicated on the extensive burden of rotavirus disease among children worldwide. US reports on nationwide hospitalizations (1979-1992) and deaths (1968-1991) due to diarrhea and weekly reports of rotavirus infection by 74 laboratories were reviewed to estimate the burden of rotavirus disease, identify epidemiologic trends, and consider methods for evaluating an immunization program when a vaccine becomes available. From 1968 to 1985, diarrhea-related deaths among US children <5 years old declined from 1100 to 300/year. This decline was associated with the disappearance of winter peaks for diarrhea-related deaths previously associated with rotavirus infection among children 4-23 months old. From 1979 to 1992, however, hospitalizations for diarrhea averaged 186,000/year and retained their winter peaks, which have been linked to rotavirus infections. Each year an estimated 54,000-55,000 US children are hospitalized for diarrhea, but <40 die with rotavirus. A rotavirus vaccine program will require improved surveillance, including the timely collection of data from sentinel hospitals, in which a diagnosis of rotavirus can be established or ruled out for all children hospitalized for diarrhea.

Child↗

PubMed1996

Trends in hospitalizations for diarrhea in United States children from 1979 through 1992: estimates of the morbidity associated with rotavirus.

OBJECTIVES: To examine trends in the hospitalizations of children for diarrheal disease in the U.S. and to provide estimates for the burden of disease associated with rotavirus diarrhea. METHODS: Data for diarrheal hospitalizations among U.S. children ages 1 month through 4 years were compiled from the National Hospital Discharge Survey for the years 1979 through 1992. Between 1979 and 1992, 12% of all hospitalizations of U.S. children 1 month through 4 years of age had an International Classification of Diseases code for diarrhea listed in one of the top three positions on the discharge diagnosis. RESULTS: The annual rate of diarrheal hospitalizations, 97 per 10 000 persons (average, 185 742 per year), did not change substantially during the 14-year study period and accounted annually for 724 394 inpatient days (3.9 days per hospitalization). For most diarrheal hospitalizations (75.9%) no causative agent was specified in the National Hospital Discharge Survey records; of the remaining 24.8%, viruses were most commonly reported (19.3%), followed by bacteria (5.1%) and parasites (0.7%). The proportion of hospitalizations associated with viral diarrheas rose from 13% to 27% during the 14-year study period, whereas the proportion of hospitalizations for noninfectious diarrhea declined from 79% to 60%. Every year the number of hospitalizations peaked from November through April, the "winter" months, among children ages 4 through 35 months; this peak began in the West during November and December and reached the Northeast by March. CONCLUSIONS: Diarrhea continues to be a common cause of hospitalization among children in the United States and the winter seasonality estimated to be caused in large part by rotavirus would be expected to decrease if rotavirus vaccines currently being developed were introduced. Our analysis of temporal trends in diarrheal hospitalizations provides a unique surrogate with which to estimate the disease burden associated with rotavirus diarrhea.

Bacterial Infections↗

PubMed1995

Trends of diarrheal disease--associated mortality in US children, 1968 through 1991.

OBJECTIVES: To describe temporal patterns in mortality related to diarrheal disease in US children and to assess progress toward its prevention and control. DESIGN: Retrospective analyses of death certificate data on diarrhea of all causes compiled by the National Center for Health Statistics, Centers for Disease Control and Prevention, Atlanta, Ga. PATIENTS: Children aged 1 month through 4 years who died with diarrhea. SETTING: United States, 1968 through 1991. RESULTS: A total of 14 137 deaths associated with diarrhea among children were reported in the United States between 1968 and 1991. Of these, 78% occurred in infants (ie, aged 1 to 11 months); the median age at the time of death has declined from 5 to 1.5 months. Diarrheal disease mortality dropped by approximately 75% during the first 18 years of the study, but no decline has occurred since 1985. Infant mortality due to diarrhea (per 100 000 live births) averaged 12.8 and was found to be high for blacks (33.1) and for residents of the southern United States (18.5). The infant mortality due to diarrhea from 1986 through 1991 is 5.9. Peaks in winter deaths previously associated with rotavirus were prominent in the early years among infants aged 4 through 11 months. Such peaks have virtually disappeared since 1985. Diarrhea was the principal cause of death, as the leading associated diagnoses (electrolyte disorders [30%], cardiac arrest [16%], shock [8%], and nausea/vomiting [4%]) were commonly recognized complications of diarrhea. Since 1979, prematurity has emerged as a common associated diagnosis. CONCLUSIONS: Diarrheal deaths nationwide have declined 75% from 1968 to 1985 but stabilized since then at about 300 deaths per year. Because many of these deaths may still be preventable by early rehydration, future prevention efforts should be directed at educating health care providers about the continuing problem and recognition of the high-risk infant and at teaching mothers of such infants to begin rehydration early and to seek medical attention when their infant develops diarrhea.

Cause of Death↗

PubMed1995

Multiple false reactions in viral antibody screening assays after influenza vaccination.

In December 1991, US blood centers reported an unusual increase in donations that tested falsely reactive for antibodies to two or more (multiple false positive) of the following viruses: human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotrophic virus type I (HTLV-I), and hepatitis C virus. Many of these donations were from people who had recently received the 1991-1992 influenza vaccine, raising the possibility that this vaccine had somehow specifically caused the problem of multiple false reactivity. A case-control study of 101 affected donors and 191 matched controls found that recent receipt of any brand of influenza vaccine was significantly associated with testing multiple false positive (p < 0.05), as was a history of recent acute illness (p < 0.05) and of allergies (p < 0.05). Surveillance for monthly rates of multiple reactive donations from May 1990 through December 1992 linked the seasonal cluster of multiple false-positive donations to the use of viral screening test kits thought to react nonspecifically to donor immunoglobulin M. There was no similar increase in multiple false-positive donations during the 1992-1993 influenza vaccination season after the HIV-1 and hepatitis C virus tests were replaced; however, the number of donations that were falsely reactive for only HTLV-I almost doubled, indicating that false reactivity was not specifically associated with the 1991-1992 influenza vaccine. Retesting of affected donors found that the duration of HTLV-I and hepatitis C virus false reactivity was 3-6 months. The cluster of multiple false-positive donations in 1991 was most likely caused by the test kits used, rather than by the influenza vaccine.

Adolescent↗

PubMed1995

Increasing mortality from thrombotic thrombocytopenic purpura in the United States--analysis of national mortality data, 1968-1991.

Thrombotic thrombocytopenic purpura (TTP) is a rare disease and the epidemiologic features have been incompletely characterized. Because of the historically high case-fatality rate for TTP, we analyzed U.S. multiple cause-of-death mortality data with TTP listed on the death record for the period 1968-1991, in order to estimate the incidence of TTP, to characterize demographic features of the decedents, and to determine if trends in mortality correlate with findings from clinical studies showing improved survival in recent years. There were 4,523 TTP-associated deaths during the 24-year study period. The annual age-adjusted mortality rate decreased initially and reached its lowest point at 0.4 per 1,000,000 residents for the years 1970 through 1973, and then increased steadily to 1.1 during the last 4 years of the study period, 1988 through 1991. We estimate the current incidence of TTP to be approximately 3.7 cases per 1,000,000 residents. Deaths were rare below the age of 20 years, but the age-specific mortality rate for those 20 years and older increased steadily with increasing age. Regardless of age, females were affected more often than males, and the overall female-to-male age-adjusted rate ratio was 1.9 (95% confidence interval (CI), 1.8 to 2.0). The greatest age-specific difference was between females and males in their twenties (rate ratio 3.2; 95% CI, 2.6 to 3.9). The mortality rate for blacks, and especially black females, was higher than the mortality rate for whites (black-to-white age-adjusted rate ratio 3.4; 95% CI, 3.2 to 3.6; black female-to-white female age-adjusted rate ratio 3.6; 95% CI, 3.3 to 3.9), although the majority of deaths were among whites (71.5%). Infection with the human immunodeficiency virus (HIV) or an HIV-related diagnosis was reported in 61 (1.3%) decedents overall and in 51 (4.4%) decedents from 1988 through 1991. The TTP mortality rate has increased over time despite reports of significant improvement in survival associated with clinical use of plasma infusion and plasma exchange. This trend in mortality suggests that the incidence of TTP is increasing. Blacks, and black females in particular, are affected at a disproportionately high rate. The increased incidence of HIV infection and related disease may have contributed to some of the increase in TTP mortality in recent years, but it does not explain the majority of the increase, which began before the onset of the HIV epidemic.

Adolescent↗

PubMed1995

Epidemiology of Creutzfeldt-Jakob disease in the United States, 1979-1990: analysis of national mortality data.

The trends and current incidence of Creutzfeldt-Jakob disease (CJD) was examined by using a unique and potentially high sensitive source for case ascertainment. We analyzed death certificate information for 1979-1990 from US multiple-cause-of-death mortality data, compiled by the National Center for Health Statistics, Centers for Disease Control and Prevention. We evaluated death certificate data for US residents for whom CJD was listed as one of the multiple causes of death on the death certificate (046.1) from the International Statistical Classification of Diseases, Injuries, and Causes of Death (9th revision). Age-adjusted and age-specific CJD death rates by gender, race, and region were calculated to measure the disease incidence because of the rapidly fatal course of the disease for most patients with CJD. We identified 2,614 deaths with CJD listed on the death certificates. The average annual age-adjusted mortality rate was 0.9 deaths per million persons (range 0.8-1.1). The mean age at death was 67 years. CJD-related deaths were uncommon among persons younger than 50 years of age (4.3% of all deaths). The highest average annual mortality rate was for those persons aged 70-74 years (5.9 deaths per million persons). A slight majority (53.0%) of the deaths was in females, but the age-adjusted mortality rate was 1.2 times higher for males. Most deaths (94.8%) were in whites; the mortality rate for blacks was only 40% of that for whites. The age-adjusted CJD mortality rate in the United States is similar to published estimates of the crude incidence of CJD worldwide.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Chronic liver disease mortality in the United States, 1979 through 1989.

OBJECTIVES: Rates and trends for chronic liver disease mortality in the United States were examined. METHODS: National Center for Health Statistics data on underlying cause of death for chronic liver disease for the United States from 1979 through 1989 were analyzed. Four groups of diseases and conditions included under the International Classification of Diseases, 9th Revision, code for chronic liver disease were assessed separately. RESULTS: From 1979 through 1989, there were 303,875 deaths from chronic liver disease; 48% were in the cirrhosis without alcohol group, 42% in the alcohol-related liver disease group, 8% in the liver disease without alcohol group, and 1.5% in the biliary cirrhosis group. Chronic liver disease death rates for Blacks were more than 1.5 times greater than those for Whites and for other races. Chronic liver disease mortality declined 22% overall among both sexes. The largest decreases were for liver disease without alcohol (42%) and cirrhosis without alcohol (25%), followed by alcohol-related liver disease (14%) and biliary cirrhosis (12%). CONCLUSION: Although declines in US chronic liver disease deaths have been attributed to declining alcohol consumption, these analyses suggest that greater declines have occurred in deaths not coded as alcohol related.

Adolescent↗

PubMed1995

National surveillance for Rocky Mountain spotted fever, 1981-1992: epidemiologic summary and evaluation of risk factors for fatal outcome.

Between 1981 and 1992, the Centers for Disease Control collected and summarized 9,223 cases of Rocky Mountain spotted fever (RMSF) reported from 46 states. Four states (North Carolina, Oklahoma, Tennessee, and South Carolina) accounted for 48% of the reports. The annual incidence per million U.S. population decreased from a high in 1981 of 5.2 to a low in 1992 of 2.0, primarily due to decreased incidence in the southeast. Case report forms were filed on 7,650 patients, of whom 4,217 had laboratory-confirmed RMSF. The age group with the highest incidence was those 5-9 years of age. Most cases (90.0%) occurred between April 1 and September 30 and included a history of tick attachment (59.6%). Reported symptoms included fever (94.0%), headache (86.2%), myalgia (82.5%), and rash (80.2%). The case-fatality ratio was 4.0%. Risk factors associated with death included older age, delay in treatment or no treatment, and treatment with chloramphenicol (compared with tetracycline); however, insufficient data existed to fully assess the confounding effect of severity of illness on antibiotic choice.

Adolescent↗

PubMed1994

Changes in longevity and causes of death among persons with hemophilia A.

To examine recent changes in longevity and the causes of death among persons with hemophilia A, we evaluated death certificate data for persons who died in the United States from 1968 through 1989 and had hemophilia A or congenital Factor VIII disorder (ICD code 286.0) listed on the death certificate as one of the multiple causes of death. Multiple-cause-of-death mortality data for the United States from 1968 to 1989 were examined to compare death rates by year, focusing on death rates and causes of death for 1979-1981, 1983-1985, and 1987-1989. Gender, age group, race, geographic region, and median age at death of persons with hemophilia A and human immunodeficiency virus (HIV)-related disease listed as a cause of death were compared with those with hemophilia A without HIV-related disease. From 1968 through 1989, 2,792 hemophilia A deaths were reported. The death rate increased from 0.5 to 1.3 per 1,000,000 persons. From 1979-1981 through 1987-1989, mortality increased in all age groups above 9 years of age and age at death shifted markedly to lower ages. Median age at death decreased from 57 years in 1979-1981 to 40 years in 1987-1989. The percentage of deaths due to hemorrhage or diseases of the circulatory system decreased markedly as the result of the increase in deaths associated with HIV infection or infections other than HIV infection. Spread of HIV-1 infection in persons with hemophilia A has disrupted the reduction in mortality seen with factor replacement therapy, implementation of home care, and use of comprehensive hemophilia treatment centers. It is hoped that advances in the care of HIV-infected persons will improve survival in the hemophilia community.

Adolescent↗

PubMed1994

Multiple unconfirmed-reactive screening tests for viral antibodies among blood donors.

BACKGROUND: In December 1991, the United States Food and Drug Administration received reports of blood donations with unconfirmed reactivity on screening tests for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus (HCV). Of 91 donors with these test results, 57 (63%) reported a recent influenza vaccination. STUDY DESIGN AND METHODS: To determine the extent of unconfirmed reactivity, the time at which it began, and its association or nonassociation with specific manufacturers' tests, a nationwide survey of blood centers was conducted. A case-donation was defined as a blood donation that was repeatedly reactive, but not confirmed positive, on at least two of the three tests from May 1990 through December 1991. RESULTS: Among 14 million donations screened by 110 centers, 582 case-donations were identified. An increase in case-donations was evident in the fall of 1990 (2.8/100,000 donations). In 1991, rates increased from 0.9 per 100,000 donations in the first quarter to 1.3, 3.2, and 19.7 in subsequent quarters. A significantly higher rate of case-donations was observed among donations tested with one of the two available anti-HCV screening tests (8.0 vs. 1.2/100,000 donations; risk ratio = 6.8; 95% CI = 5.4-8.5). CONCLUSION: Although unconfirmed reactivity on multiple screening tests appeared to be seasonal, its documentation prior to the availability of influenza vaccine in 1991 and higher rates among donations tested with one manufacturer's anti-HCV test indicated that test-specific factors were also involved.

Antibodies, Viral↗