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CONCISE COMMUNICATIONS
Risk of Viral Hepatitis among Military Personnel Assigned to US Navy Ships Richard E. Hawkins, John D. Malone, Lee A. Cloninger, Patrick J. Rozmajzl, Drew Lewis, James Butler, Eleanor Cross, Stephanie Gray, and Kenneth C. Hyams
Departments of Internal Medicine and of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Infectious Disease Division. Bethesda Naval Hospital. and Epidemiology Division. Naval Medical Research Institute. Bethesda. Maryland; US Navy Environmental and Preventive Medicine Unit No.7, Naples. Italy; Internal Medicine Department, Naval Hospital, Groton. Connecticut
Viral hepatitis has been a major problem for the United States military [1]. The risk of viral hepatitis has generally been found to be higher in military personnel than in civilian populations because of risk factors characteristic of military populations, such as communal living conditions, former patterns of illicit drug use, and exposure in developing countries where viral hepatitis is endemic [2-6]. Studies by the US Army have indicated an increased risk of viral hepatitis in soldiers stationed in South Korea [7, 8]. However, the risk of viral hepatitis infection in deployed shipboard personnel who are potentially exposed to these agents during port visits is not well understood [9, 10]. The objective ofthis study was to determine whether assignment outside of the United States is associated with hepatitis A, B, or C in shipboard US Navy and Marine Corps personnel.
Received 16 September 1991; revised 14 November 1991. Presented in part: 39th annual meeting. American Society of Tropical Medicine and Hygiene. New Orleans, 1990 (abstract 258). Informed consent was obtained from study subjects. and the research guidelines of the US Naval Medical Research Institute Committee for the Protection of Human Subjects were followed. The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the US Department of the Navy or Department of Defense. Financial support: Naval Medical Research and Development Command, National Capital Region (work unit no. 3MI62770AR122). Reprints or correspondence: Dr. Richard E. Hawkins. Infectious Disease Division, National Naval Medical Center, Bethesda. MD 20889-1000. The Journal of Infectious Diseases 1992;165:716-9 © 1992 by The University of Chicago. All rights reserved. 0022-1899/92/6504-0017$01.00
Methods Six US Navy ships scheduled for a 6-month deployment to South America and West Africa (July 1989 to December 1989) and five ships scheduled for a 6-month deployment to the Mediterranean (July 1990 to January 1991) were chosen for this study. Multiple port visits were made by these ships along the Atlantic and Pacific coasts of South America, the coast of West Africa, and in eight countries on the Mediterranean Sea. All crew members and Marine Corps personnel assigned to ships scheduled for South America/West Africa deployment and all marines assigned to ships scheduled for Mediterranean deployment were invited to participate in the study. About 50% of eligible subjects volunteered. The major reason for nonparticipation was absence from the ship or base when the survey was being conducted. A 15-ml blood sample was collected from each subject before deployment; a second sample was obtained from all available subjects 6 months later, immediately before return to the US mainland. Serum samples were tested by EIA (Abbott Laboratories, North Chicago) for antibodies to hepatitis A virus (total anti-HAY), to hepatitis B core antigen (total anti-Hlsc), and to hepatitis C virus (total anti-HCV). Samples positive for antiHBc were tested for hepatitis B surface antigen (HBsAg), and sera positive for HBsAg were tested for antibodies to hepatitis delta virus (anti-HDV) by EIA (Abbott). Seroconverters were also tested for anti-HBc IgM (Abbott). Only samples that were positive twice in two separate assays were considered positive. Samples positive by EIA for anti-HCV were also verified with a second-generation imrnunoblot assay (RIBA HCV TEST SYSTEM; Chiron, Emeryville, CA). Study questionnaires were administered before and after deployment, at the same time as blood sample collection, to small
Downloaded from http://jid.oxfordjournals.org/ at University of Aberdeen on February 14, 2015
A prevalence study of2072 male US shipboard military personnel scheduled for deployment to South America/West Africa and the Mediterranean was conducted to determine whether serologic evidence of prior hepatitis A, B, or C infection is associated with exposure in foreign countries. There were 210 subjects (10.1 %) who had antibodies to hepatitis A virus (anti-HAV), 76 (3.7%) to hepatitis B core antigen (anti-HBc), and 9 (0.4%) to hepatitis C virus (anti-HCV). By multivariate analysis, anti-HAV seropositivity was independently associated with age, nonwhite racial/ethnic groups, birth outside of the United States, and prior Caribbean deployment for 1 year). No geographic risk factors were associated with anti-HCV positivity. These data indicate that military personnel deployed outside the United States are at increased risk of viral hepatitis infection and should be considered for vaccination.
JlO 1992;165 (April)
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Concise Communications
Results Study population. There were 2072 subjects initially entered into the study, 1059 before the South America/West African deployment and 1013 before the Mediterranean deployment. The mean age of study subjects was 24 years (range, 18-50). The racial/ethnic composition of participants was 71.7% white, 18.6% black, 7.1 %hispanic, 0.8% Filipino, and 1.8% other. Ninety-six percent of subjects were enlisted. Most (98%) had completed high school; 6% had completed college. Marines constituted 58% and naval personnel42% of the study population. Study subjects had been on active duty for a mean of 4.4 years (range, 1-28). Hepatitis A prevalence study. Of 2072 study subjects evaluated before deployment, 210 (10.1 %)were seropositive for anti-HAY. There was a steady increase in prevalence of anti-HAY with age, from 7.8% in subjects 18-24 years old to 28.7% in subjects >34 years old. Fifty percent of28 subjects reporting a history ofacute hepatitis were anti-HAV-positive compared with 9.6% of individuals without a history ofhepatitis (P < .001). In bivariate analysis, the prevalence of anti-HAV was increased in nonwhite racial/ethnic groups, enlisted personnel, subjects born outside of the United States, and subjects who had been on duty for> 12 months in the Mediterranean (table 1). By multivariate analysis, age, nonwhite racial/ethnic groups, and birth outside of the United States were independently associated with anti-HAV seropositivity (table 2). Re-
Table t.
Hepatitis A and B seroprevalence in 2072 US Navy and Marine Corps personnel by selected demographic characteristics and prior overseasassignments. % (no. positive/no. responding)* Factor Rank Enlisted Officer Race/ethnicity White Black Hispanic Filipino Other Birth location United States Foreign Prior deployment" Caribbean Mediterranean Scandinavia Okinawa South Pacific Africa Prior duty" Mediterranean Okinawa South Pacific
Anti-HAV
10.4 (206/1986) 4.7 (4/85) 5.0 14.3 36.1 88.2 36.1
(74/1485) (55/385) (53/147) (15/17) (13/36)
8.0 (155/1932) 39.3 (55/140) 11.3 11.5 12.2 7.7 13.2 14.3
(107/951) (97/842) (16/131) (21/271) (31/235) (2/14)
22.2 (8/36) 9.3 (9/97) 3.8 (2/52)
Anti-HBc
3.7 (73/1986) 3.5 (3/85) 2.9 (43/1485) 5.2 (20/385) 2.0 (3/147) 41.2(7/17) 8.3 (3/36) 3.2 (61/1932) to.7 (15/140) 3.5 (33/951) 4.0 (34/842) 6.1 (8/131) 2.2 (6/271) 9.8 (23/235) 0(0/14) 19.4 (7/36) 6.2 (6/97) 17.3 (9/52)
* Variations in denominator totals reflect incomplete responses to questions. HAV, hepatitis A virus; HBc, hepatitis B core antigen. t Deployment. < 12 months; duty, > 12 months.
sults ofevaluation ofprior assignments by multivariate analysis differed from those by bivariate analysis: An independent association was found between anti-HAV positivity and prior Caribbean deployment ( < 1 year) but not prior duty in the Mediterranean, after adjustment for other risk factors. Hepatitis B prevalence study. Seventy-six subjects (3.7%) were seropositive for anti-HBc, five had HBsAg, and none was positive for anti-HDV. There was a general trend of increasing prevalence of anti-HBc with increasing age: 2.2% in subjects 18-24,7.2% in subjects 25-34, and 8.3% in subjects > 34 years old. Subjects with a history of hepatitis were more likely to have anti-HBc (14.3% compared with 3.5%; P = .01). In bivariate analysis, anti-HBc was found most commonly in Filipino subjects and in those born outside the United States (table 1). Analysis of prior assignments indicated an increased risk of anti-HBc positivity in participants who had been deployed «12 months) to the South Pacific or Indian Ocean and who had been on duty (> 1 year) in the South Pacific or Mediterranean. The prevalence ofanti-HBc was higher in the 387 subjects (19%) with a history of a sexually transmitted disease (STD; 6.7% vs. 3,0%; P = .007). Although there was an association
Downloaded from http://jid.oxfordjournals.org/ at University of Aberdeen on February 14, 2015
groups of subjects after full explanation of each question. The initial questionnaire elicited basic demographic information and details about prior transmission risk factors, including prior foreign assignments. Information was obtained about previous deployment ( < 12 months) to the Caribbean, Okinawa, the South Pacific or Indian Ocean, Africa, the Mediterranean, and Scandinavia, and participants were asked about duty (> 12 months) to Okinawa, the South Pacific, and the Mediterranean. In the postdeployment questionnaire, study subjects were asked about possible exposure factors and illness compatible with viral hepatitis during the immediately preceding deployment. The laboratory results from the initial blood sample and questionnaire data were used in a cross-sectional prevalence study of risk factors associated with seropositivity for hepatitis markers. In a separate incidence study, postdeployment serologic testing results were compared with predeployment results to evaluate the risk of infection during the 6-month study period. Proportions were compared using the x 2 test with Yates's correction or Fisher's exact test. Multiple logistic regression analysis was done using the SPSS/PC statistical package (SPSS, Chicago). Two final models were developed with the presence or absence of anti-HA V and anti-HBc as the dichotomous outcome variable. The likelihood ratio test was used in a backward selection process with subsequent readdition of individual variables to the model. Odds ratios were reported with 95% confidence intervals.
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Table 2.
Final logistic regression models with variables independently associated with hepatitis A and B seropositivity after adjustment for age in 2072 US Navy and Marine Corps personnel.
Variable
1.09(1.06-1.12) 3.5 (2.4-5.1) 10.4 (6.6-16.0) 40.8(8.4-197.0) 7.7 (3.5-17.0) 2.4 (1.5-3.9) 1.2(1.01-1.4)
P
CONCISE COMMUNICATIONS
Risk of Viral Hepatitis among Military Personnel Assigned to US Navy Ships Richard E. Hawkins, John D. Malone, Lee A. Cloninger, Patrick J. Rozmajzl, Drew Lewis, James Butler, Eleanor Cross, Stephanie Gray, and Kenneth C. Hyams
Departments of Internal Medicine and of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Infectious Disease Division. Bethesda Naval Hospital. and Epidemiology Division. Naval Medical Research Institute. Bethesda. Maryland; US Navy Environmental and Preventive Medicine Unit No.7, Naples. Italy; Internal Medicine Department, Naval Hospital, Groton. Connecticut
Viral hepatitis has been a major problem for the United States military [1]. The risk of viral hepatitis has generally been found to be higher in military personnel than in civilian populations because of risk factors characteristic of military populations, such as communal living conditions, former patterns of illicit drug use, and exposure in developing countries where viral hepatitis is endemic [2-6]. Studies by the US Army have indicated an increased risk of viral hepatitis in soldiers stationed in South Korea [7, 8]. However, the risk of viral hepatitis infection in deployed shipboard personnel who are potentially exposed to these agents during port visits is not well understood [9, 10]. The objective ofthis study was to determine whether assignment outside of the United States is associated with hepatitis A, B, or C in shipboard US Navy and Marine Corps personnel.
Received 16 September 1991; revised 14 November 1991. Presented in part: 39th annual meeting. American Society of Tropical Medicine and Hygiene. New Orleans, 1990 (abstract 258). Informed consent was obtained from study subjects. and the research guidelines of the US Naval Medical Research Institute Committee for the Protection of Human Subjects were followed. The opinions and assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the US Department of the Navy or Department of Defense. Financial support: Naval Medical Research and Development Command, National Capital Region (work unit no. 3MI62770AR122). Reprints or correspondence: Dr. Richard E. Hawkins. Infectious Disease Division, National Naval Medical Center, Bethesda. MD 20889-1000. The Journal of Infectious Diseases 1992;165:716-9 © 1992 by The University of Chicago. All rights reserved. 0022-1899/92/6504-0017$01.00
Methods Six US Navy ships scheduled for a 6-month deployment to South America and West Africa (July 1989 to December 1989) and five ships scheduled for a 6-month deployment to the Mediterranean (July 1990 to January 1991) were chosen for this study. Multiple port visits were made by these ships along the Atlantic and Pacific coasts of South America, the coast of West Africa, and in eight countries on the Mediterranean Sea. All crew members and Marine Corps personnel assigned to ships scheduled for South America/West Africa deployment and all marines assigned to ships scheduled for Mediterranean deployment were invited to participate in the study. About 50% of eligible subjects volunteered. The major reason for nonparticipation was absence from the ship or base when the survey was being conducted. A 15-ml blood sample was collected from each subject before deployment; a second sample was obtained from all available subjects 6 months later, immediately before return to the US mainland. Serum samples were tested by EIA (Abbott Laboratories, North Chicago) for antibodies to hepatitis A virus (total anti-HAY), to hepatitis B core antigen (total anti-Hlsc), and to hepatitis C virus (total anti-HCV). Samples positive for antiHBc were tested for hepatitis B surface antigen (HBsAg), and sera positive for HBsAg were tested for antibodies to hepatitis delta virus (anti-HDV) by EIA (Abbott). Seroconverters were also tested for anti-HBc IgM (Abbott). Only samples that were positive twice in two separate assays were considered positive. Samples positive by EIA for anti-HCV were also verified with a second-generation imrnunoblot assay (RIBA HCV TEST SYSTEM; Chiron, Emeryville, CA). Study questionnaires were administered before and after deployment, at the same time as blood sample collection, to small
Downloaded from http://jid.oxfordjournals.org/ at University of Aberdeen on February 14, 2015
A prevalence study of2072 male US shipboard military personnel scheduled for deployment to South America/West Africa and the Mediterranean was conducted to determine whether serologic evidence of prior hepatitis A, B, or C infection is associated with exposure in foreign countries. There were 210 subjects (10.1 %) who had antibodies to hepatitis A virus (anti-HAV), 76 (3.7%) to hepatitis B core antigen (anti-HBc), and 9 (0.4%) to hepatitis C virus (anti-HCV). By multivariate analysis, anti-HAV seropositivity was independently associated with age, nonwhite racial/ethnic groups, birth outside of the United States, and prior Caribbean deployment for 1 year). No geographic risk factors were associated with anti-HCV positivity. These data indicate that military personnel deployed outside the United States are at increased risk of viral hepatitis infection and should be considered for vaccination.
JlO 1992;165 (April)
717
Concise Communications
Results Study population. There were 2072 subjects initially entered into the study, 1059 before the South America/West African deployment and 1013 before the Mediterranean deployment. The mean age of study subjects was 24 years (range, 18-50). The racial/ethnic composition of participants was 71.7% white, 18.6% black, 7.1 %hispanic, 0.8% Filipino, and 1.8% other. Ninety-six percent of subjects were enlisted. Most (98%) had completed high school; 6% had completed college. Marines constituted 58% and naval personnel42% of the study population. Study subjects had been on active duty for a mean of 4.4 years (range, 1-28). Hepatitis A prevalence study. Of 2072 study subjects evaluated before deployment, 210 (10.1 %)were seropositive for anti-HAY. There was a steady increase in prevalence of anti-HAY with age, from 7.8% in subjects 18-24 years old to 28.7% in subjects >34 years old. Fifty percent of28 subjects reporting a history ofacute hepatitis were anti-HAV-positive compared with 9.6% of individuals without a history ofhepatitis (P < .001). In bivariate analysis, the prevalence of anti-HAV was increased in nonwhite racial/ethnic groups, enlisted personnel, subjects born outside of the United States, and subjects who had been on duty for> 12 months in the Mediterranean (table 1). By multivariate analysis, age, nonwhite racial/ethnic groups, and birth outside of the United States were independently associated with anti-HAV seropositivity (table 2). Re-
Table t.
Hepatitis A and B seroprevalence in 2072 US Navy and Marine Corps personnel by selected demographic characteristics and prior overseasassignments. % (no. positive/no. responding)* Factor Rank Enlisted Officer Race/ethnicity White Black Hispanic Filipino Other Birth location United States Foreign Prior deployment" Caribbean Mediterranean Scandinavia Okinawa South Pacific Africa Prior duty" Mediterranean Okinawa South Pacific
Anti-HAV
10.4 (206/1986) 4.7 (4/85) 5.0 14.3 36.1 88.2 36.1
(74/1485) (55/385) (53/147) (15/17) (13/36)
8.0 (155/1932) 39.3 (55/140) 11.3 11.5 12.2 7.7 13.2 14.3
(107/951) (97/842) (16/131) (21/271) (31/235) (2/14)
22.2 (8/36) 9.3 (9/97) 3.8 (2/52)
Anti-HBc
3.7 (73/1986) 3.5 (3/85) 2.9 (43/1485) 5.2 (20/385) 2.0 (3/147) 41.2(7/17) 8.3 (3/36) 3.2 (61/1932) to.7 (15/140) 3.5 (33/951) 4.0 (34/842) 6.1 (8/131) 2.2 (6/271) 9.8 (23/235) 0(0/14) 19.4 (7/36) 6.2 (6/97) 17.3 (9/52)
* Variations in denominator totals reflect incomplete responses to questions. HAV, hepatitis A virus; HBc, hepatitis B core antigen. t Deployment. < 12 months; duty, > 12 months.
sults ofevaluation ofprior assignments by multivariate analysis differed from those by bivariate analysis: An independent association was found between anti-HAV positivity and prior Caribbean deployment ( < 1 year) but not prior duty in the Mediterranean, after adjustment for other risk factors. Hepatitis B prevalence study. Seventy-six subjects (3.7%) were seropositive for anti-HBc, five had HBsAg, and none was positive for anti-HDV. There was a general trend of increasing prevalence of anti-HBc with increasing age: 2.2% in subjects 18-24,7.2% in subjects 25-34, and 8.3% in subjects > 34 years old. Subjects with a history of hepatitis were more likely to have anti-HBc (14.3% compared with 3.5%; P = .01). In bivariate analysis, anti-HBc was found most commonly in Filipino subjects and in those born outside the United States (table 1). Analysis of prior assignments indicated an increased risk of anti-HBc positivity in participants who had been deployed «12 months) to the South Pacific or Indian Ocean and who had been on duty (> 1 year) in the South Pacific or Mediterranean. The prevalence ofanti-HBc was higher in the 387 subjects (19%) with a history of a sexually transmitted disease (STD; 6.7% vs. 3,0%; P = .007). Although there was an association
Downloaded from http://jid.oxfordjournals.org/ at University of Aberdeen on February 14, 2015
groups of subjects after full explanation of each question. The initial questionnaire elicited basic demographic information and details about prior transmission risk factors, including prior foreign assignments. Information was obtained about previous deployment ( < 12 months) to the Caribbean, Okinawa, the South Pacific or Indian Ocean, Africa, the Mediterranean, and Scandinavia, and participants were asked about duty (> 12 months) to Okinawa, the South Pacific, and the Mediterranean. In the postdeployment questionnaire, study subjects were asked about possible exposure factors and illness compatible with viral hepatitis during the immediately preceding deployment. The laboratory results from the initial blood sample and questionnaire data were used in a cross-sectional prevalence study of risk factors associated with seropositivity for hepatitis markers. In a separate incidence study, postdeployment serologic testing results were compared with predeployment results to evaluate the risk of infection during the 6-month study period. Proportions were compared using the x 2 test with Yates's correction or Fisher's exact test. Multiple logistic regression analysis was done using the SPSS/PC statistical package (SPSS, Chicago). Two final models were developed with the presence or absence of anti-HA V and anti-HBc as the dichotomous outcome variable. The likelihood ratio test was used in a backward selection process with subsequent readdition of individual variables to the model. Odds ratios were reported with 95% confidence intervals.
718
Concise Communications
Table 2.
Final logistic regression models with variables independently associated with hepatitis A and B seropositivity after adjustment for age in 2072 US Navy and Marine Corps personnel.
Variable
1.09(1.06-1.12) 3.5 (2.4-5.1) 10.4 (6.6-16.0) 40.8(8.4-197.0) 7.7 (3.5-17.0) 2.4 (1.5-3.9) 1.2(1.01-1.4)
P
