Hepatitis B vaccine booster dose: low-dose recombinant hepatitis B vaccines as a booster dose.

BACKGROUND: The timing and best regimen for a booster dose of hepatitis B vaccine have not been determined. METHODS: Two studies were conducted to determine the response to a booster dose of 5 micrograms recombinant hepatitis B vaccine. In the first study, a 5 micrograms (0.5 ml) dose of Recombivax HB was administered intramuscularly 38 months after the initial dose to 71 volunteers. In a second study, we offered a 5 micrograms dose recombinant hepatitis B vaccine, either Recombivax HB (0.5 ml) or Engerix B (0.25 ml), to students who had previously been immunized with three doses of vaccine. RESULTS: In the first study, among the 44 persons for whom postbooster sera were available, the geometric mean concentration of anti-hepatitis B surface antigens increased from 42 to 2090 mIU/ml after the 5 micrograms (0.5 ml) dose of Recombivax. In the second study, after a 5 micrograms (0.5 ml) dose of Recombivax, the geometric mean concentration increased from 43 to 990 mIU/ml (n = 48), and in the group that received a 5 micrograms (0.25 ml) dose of Engerix B, the concentration increased from 83 to 2337 mIU/ml (n = 45) (p = 0.18 for postdose concentrations). CONCLUSION: A 5 micrograms dose of recombinant vaccine results in an excellent booster response at a cost one fourth to one half that of a full 1 ml dose of vaccine.

Disease threats in Somalia.

During this time of war and famine in Somalia, disease threats are encyclopedic both for Somalis and visitors. Malnutrition will amplify the magnitude and severity of endemic tropical infectious diseases. Necessary crowding around life-saving food distribution centers could turn focal infectious disease outbreaks into large epidemics.

An outbreak of enterically transmitted non-A, non-B hepatitis in Pakistan.

An epidemic of enterically transmitted non-A, non-B hepatitis occurred at a college in Sargodha, Pakistan in early 1987. There were 133 clinical cases, an attack rate of approximately 20%. Though the disease was relatively mild, all clinical cases required hospitalization and prolonged convalescence. Nearly all cases were associated with a single water source. The epidemic ended when the water supply was improved. This is the 4th described epidemic of non-A, non-B hepatitis in Pakistan.

Predictions of malaria vector distribution in Belize based on multispectral satellite data.

Use of multispectral satellite data to predict arthropod-borne disease trouble spots is dependent on clear understandings of environmental factors that determine the presence of disease vectors. A blind test of remote sensing-based predictions for the spatial distribution of a malaria vector, Anopheles pseudopunctipennis, was conducted as a follow-up to two years of studies on vector-environmental relationships in Belize. Four of eight sites that were predicted to be high probability locations for presence of An. pseudopunctipennis were positive and all low probability sites (0 of 12) were negative. The absence of An. pseudopunctipennis at four high probability locations probably reflects the low densities that seem to characterize field populations of this species, i.e., the population densities were below the threshold of our sampling effort. Another important malaria vector, An. darlingi, was also present at all high probability sites and absent at all low probability sites. Anopheles darlingi, like An. pseudopunctipennis, is a riverine species. Prior to these collections at ecologically defined locations, this species was last detected in Belize in 1946.

Initial report of a hepatitis investigation in rural Belize.

In spring 1991, Belizian health officials expressed concern about a possible hepatitis outbreak in a banana farming district. A study was designed to identify cases and to address the serological prevalence of hepatitis virus markers. Three populations were studied: (i) persons meeting a clinical case definition for hepatitis; (ii) designated banana workers; and (iii) people in a random sample of households in the community. Information was collected using questionnaires and sera were collected for laboratory testing. This report presents the preliminary results of a study conducted in June 1991. Among people who met the clinical case definition, 24% of 42 tested had immunoglobulin M antibody to hepatitis B virus (HBV) core antigen (anti-HBc IgM). In the worker and household survey populations, 284 and 280 people, respectively, were tested for anti-HBc IgM. In each group, 4% were positive. HBV surface antigen was found in 37% of 43 clinical cases, 18% of workers, and 13% of people in the household survey. Among the 3 study populations, the prevalence of HBV core antibody (anti-HBc) ranged from 73% to 81%. Almost all tested persons had evidence of prior hepatitis A virus infection. Evidence of prior infection with hepatitis viruses A and B was widespread, but an aetiology could not be established for most of the clinical cases. However, the prevalence of hepatitis B markers in this population was very high compared to other reports from the Caribbean.

Preliminary observations on the changing roles of malaria vectors in southern Belize.

A survey for larval and adult Anopheles mosquitoes was conducted in Toledo District of southern Belize during August-September 1992. We surveyed for larvae in 145 habitats and conducted paired indoor-outdoor collections of adult mosquitoes landing on humans at 6 houses. In 1940-41, Kumm and Ram reported Anopheles darlingi females to be the most common Anopheles mosquitoes inside houses and reported no specimens of Anopheles vestitipennis in southern Belize. In our 1992 survey we found no An. darlingi mosquitoes either as adults or larvae. More An. vestitipennis females were captured indoors than outdoors, whereas most Anopheles albimanus and Anopheles apicimacula females were captured outdoors. All 3 species were represented occasionally in 145 collections of larvae from diverse habitats. Anopheles vestitipennis now appears to be a potentially important vector of malaria during the wet season in Toledo District.

PIP: Kumm and Ram surveyed for the presence of larval and adult Anopheles mosquitoes in Belize in 1940-41. They found An. darlingi to be the most common of Anopheles species inside houses and reported observing no An. vestitipennis in southern Belize. That study was conducted before the DDT malaria control program was implemented in the country and offers the most recent publication of such findings for the area up to the publication of this more recent report by the authors. The authors report findings from a recent survey of larval and adult Anopheles mosquitoes in the Toledo District during August-September 1992. The presence of larvae was surveyed in 145 habitats, while paired indoor-outdoor collections of adult mosquitoes landing on humans were taken at six houses. The authors, however, report finding no An. darlingi mosquitoes, either as adults or larvae. More An. vestitipennis females were captured indoors than outdoors and most An. albimanus and An. apicimacula females were captured outdoors. All three species were represented occasionally in the collections of larvae from diverse habitats. These findings clearly suggest that An. vestitipennis is a potentially important vector of malaria in the wet season in Toledo District.

The role of military medicine in military civic action.

We are moving into an era when U.S. military forces will be called upon frequently to perform military civic action (MCA) projects. Such projects, have been used successfully and unsuccessfully, primarily in the areas of medicine and engineering, to enhance the standing of military forces with indigenous populations. However, the available criteria for planning and assessing MCA projects are not widely known. These related and overlapping criteria are supported by facts, interpretative data, anecdotes, and common sense, but none can be considered absolute. Selected criteria are defined, reviewed, and illustrated with examples of past successes and failures.

Randomized controlled trial of concurrent hepatitis A and B vaccination.

Hepatitis A and B viruses are threats to deployed military forces. The objective of this study was to determine the feasibility of concurrent vaccination against hepatitis A and B viruses. One hundred five healthy persons, 20 to 49 years of age and without serologic markers to hepatitis A or B viruses, were randomized to receive an inactivated hepatitis A vaccine (HEP A; 25 units in 0.5 mL), recombinant hepatitis B vaccine (HEP B; 10 micrograms in 1.0 mL), or both (HEP A & B) concurrently in separate arms. Vaccines were administered intramuscularly at 0, 1, and 6 months. Sera obtained at 1, 2, 6, 7, and 12 months after the first dose were tested for quantitative antibody to hepatitis A virus (anti-HAV) and antibody to hepatitis B surface antigen. Local reactions (e.g., pain) were reported by less than half of the volunteers and were similar at the site of HEP A, whether given alone or concurrently. However, more persons complained of pain (usually mild) at the HEP B site when HEP B was given concurrently with HEP A compared with HEP B alone (43% vs. 15%, 34% vs. 9%, and 42% vs. 15% for doses 1, 2, and 3, respectively; p < 0.05 for each dose). Among persons immunized with HEP A alone or HEP A & B, the proportion with > or = 10 mIU/mL anti-HAV was 83% in both groups 1 month after dose 1 and 100% at months 2, 7, and 12. The geometric mean concentrations of anti-HAV increased from 21 mIU/mL at month 1 to 2,649 and 2,312 mIU/mL in the HEP A and HEP A & B groups, respectively, at month 7. The response to HEP B was similar whether administered alone or concurrently. Antibody responses were similar in those receiving HEP A or HEP B concurrently or alone, but more subjects reported pain (usually mild) at the HEP B site after concurrent vaccination than after HEP B alone. Further work should be conducted to approve HEP A for patients younger than 2 years of age and to develop combined HEP A and HEP B vaccines in the United States.

Prevalence of sand fly fever, West Nile, Crimean-Congo hemorrhagic fever, and leptospirosis antibodies in Pakistani military personnel.

To determine the prevalence of antibodies to viral diseases known or suspected to be present in Pakistan, we studied 570 sera from three groups of adults; two of the groups were involved in outbreaks of hepatitis, and the third included men admitted to a hospital for evaluation of febrile illnesses. Immunoglobulin G antileptospiral antibody was found in 1 to 6% of the subjects, with the highest rate in enlisted military personnel hospitalized for febrile illness. One man in the group with febrile illness had significantly elevated immunoglobulin M antileptospiral antibody titers. However, in a group of recruits experiencing suspected non-A, non-B hepatitis, 19 (11%) of 173 had a 4-fold rise in immunoglobulin M antibody to leptospirosis. Antibody to sand fly fever viruses was found in 27 to 70%. Antibody to West Nile virus was present in 33 to 41% of subjects. Antibody reactive with Japanese encephalitis virus was present in 25%, but plaque reduction neutralization tests suggested this to be cross-reaction with West Nile virus. All 212 specimens tested for antibody to Crimean-Congo hemorrhagic fever and Hantaan viruses were negative. This study indicates that diseases known to be prevalent in other areas of southwest Asia and the Middle East are also prevalent in northern Pakistan and may impact on those traveling or working in this area.

Hepatitis C as a cause of chronic liver disease in northern Pakistan.

The antibodies to hepatitis C virus (HCV) were tested in 45 histologically confirmed cases of chronic liver disease. Twelve cases had chronic hepatitis, 24 cirrhosis and 9 hepatocellular carcinoma. Anti-HCV was detected in 6 patients. Two (16.67%) were suffering from chronic hepatitis, 3 (12.5%) had cirrhosis and one (11.11%) hepatocellular carcinoma. None of the anti-HCV positive cases had past history of blood transfusion. The patients of chronic liver disease in this study had a much higher prevalence of HBV infection which indicates that in northern Pakistan hepatitis C virus infection is not a common cause of chronic liver disease whereas HBV infection plays an aetiological role in a much larger number of these cases.