G. Gentili

Incidence and determinants of hepatitis C virus infection among individuals at risk of sexually transmitted diseases attending a human immunodeficiency virus type 1 testing program.

Background: The role of sexual transmission of hepatitis C virus (HCV) infection is still not completely understood, partly because of the lack of longitudinal studies among cohorts of HCV‐negative individuals who engage in at‐risk sexual behavior. Goals: To evaluate the incidence of HCV infection in a population at risk for human immunodeficiency virus type 1 (HIV‐1) infection and other sexually transmitted diseases (STD) and to identify factors associated with HCV seroconversion. Study Design: A retrospective longitudinal study was carried out on a cohort of consecutive attendees of a voluntary HIV‐1 testing and counseling program in a large STD center in Rome. All individuals undergoing at least two consecutive tests for HCV antibodies were enrolled. Clinical data and information on individual behavior were collected for all study participants. Results: Between June, 1992 and December, 1994, a total of 709 individuals (12 intravenous drug users [IDU], 244 homosexuals, and 453 heterosexual non‐IDUs), initially negative for HCV antibody, were tested more than once. Among these individuals, 15 HCV seroconversions occurred. The average follow‐up time was 1.25 person/years (p/y) for an incidence rate of 1.69 per 100 p/y. The incidence rates by exposure category were 39.30 per 100 p/y among IDUs, 1.37 per 100 p/y among homosexual men, and 0.97 per 100 p/y among heterosexual non‐IDUs. Excluding IDUs, of the 697 STD clinic attendees engaging in at‐risk sexual behavior, HIV‐1‐positive status tended to be associated with HCV seroconversion (relative hazard = 5.48; 95% confidence interval = 0.85–35.40). The HCV crude incidence rates among HIV‐1‐infected patients at enrollment was 11.5%, 4.2%, and 2.4% in those with severe, moderate, and mild levels of immunosuppression, respectively (chi‐square for trend = 2.38, P = 0.1). Conclusions: In this cohort, HCV infection was confirmed to be strongly associated with intravenous drug use. Nonetheless, the occurrence of two thirds of the total HCV seroconversions in non‐IDU individuals engaging in at‐risk behavior suggests a role of sexual practices in the transmission of the infection. Among non‐IDU individuals, the risk for development of HCV infection tended to increase in those who were HIV‐1 infected.

Hepatitis B and Delta virus infection among heterosexuals, homosexuals and bisexual men

The hepatitis B virus (HBV) and hepatitis Delta virus (HDV) infection rates were estimated in patients attending a venereal disease outpatient clinic: 759 heterosexuals and 154 homosexual-bisexual men. The anti-HBC prevalence was higher in homo-bisexual men (68.8 per 100) than in heterosexuals (41.8 per 100), whereas HBsAg was roughly the same in the two groups (about 6 per 100). The anti-HBc prevalence rate among heterosexuals was higher than that estimated in hospital personnel from the same geographical area. A positive association between anti-HBc prevalence and present or past sexually transmitted diseases (STD) was found among homo-bisexual men. Anti-HBc was also positively associated with herpes simplex type 2 antibodies in both heterosexuals and homo-bisexual men. These data are consistent with the hypothesis that sexual behavior also plays a role in the spread of infection among heterosexuals. Ten of the 46 HBsAg-positive subjects were anti-HDV positive: 6 of the 36 heterosexuals and 4 of the 10 homosexuals. All HDV-positive subjects had present or past STDs. These findings suggest sexual transmission of HDV infection.

Genital herpes infection in outpatients attending a sexually transmitted disease clinic in Italy.

Prevalence of Herpes Simplex, type 2, specific antibodies was estimated in sexually transmitted disease outpatients: 783 heterosexuals and 158 homosexual-bisexuals. The anti-HSV-2 prevalence rates were 69% in the homosexual-bisexuals and 35% in the heterosexuals. In both groups positive association with age of anti-HSV-2 prevalence was found: only in the homosexual-bisexuals negative as sociation with education level was detected. No difference exists between the two groups regarding the symptomatic/asymptomatic ratio of HSV-2 infection.

Risk factors for hepatitis B virus infection among heterosexuals attending a sexually transmitted diseases clinic in Italy: Role of genital ulcerative diseases

The seroprevalence and risk factors for hepatitis B virus (HBV) infection were determined among 1,497 heterosexuals with no history of intravenous drug use (median age 32, range 15–78) treated at a sexually transmitted disease clinic in Rome. A total of 329 (22.0%) had antibodies to HBV core antigen (anti‐HBc), a rate nearly four times as high as the 5.8% found recently in a national sample of young male adults, ages 18–26 years. Multiple logistic regression analysis showed that the risk of anti‐HBc positivity was independently associated with male sex, increasing age, lower level of education, three or more sexual partners in the previous year, and positive syphilis serology. Lack of condom use, history of nonulcerative sexually transmitted diseases, and genital herpes were not associated with anti‐HBc positivity. These findings confirm that heterosexual exposure plays an important role in the spread of HBV infection. Furthermore, these data indicate that individuals with more than two sexual partners a year and those with positive syphilis serology should be immunised against HBV.

Seroprevalence of anti-Chlamydia trachomatis IgG in outpatients attending a sexually transmitted disease clinic in Italy

Prevalence of anti-Chlamydia trachomatis specific IgG antibodies was evaluated in a sexually transmitted disease outpatient population composed of 741 heterosexuals, 470 males and 271 females, and of 147 homosexual-bisexual men. The prevalence rates were 60.0% in heterosexual males, 50.6% in females and 73.5% in homosexuals-bisexuals. A positive association between age and antibody prevalence was found in males. Among heterosexuals there is an increasing trend of seropositivity with number of partners during the previous year. A significant association between anti-chlamydial and anti-herpes simplex, type 2, antibodies has been demonstrated.

Immunity to tetanus among Italians born between 1956 and 1963

Systematic mandatory immunization of children against tetanus begun in Italy in 1968. Preceeding birth cohorts, accounting for almost 80% of present Italian population, were poorly immune or totally non-immune; around 90% of cases of tetanus occurring in Italy in recent years are observed among them.In a national sample of 4770 young males born between 1956 and 1963, about one third was not protected. Prevalence of non-immune subjects was greater in the Southern Regions and the Islands, in rural areas, among the unemployed, among the older birth cohorts.

PREVALENCE OF HYPERIMMUNIZATION AGAINST TETANUS IN ITALIANS BORN AFTER THE INTRODUCTION OF MANDATORY VACCINATION OF CHILDREN WITH TETANUS TOXOID IN 1968

SummarySystematic mandatory immunization of children against tetanus was started in Italy in 1968. Prevalence of tetanus hyperimmunization (>5 IU/ml) was assessed among 214 immune subjects born after 1968 and found to be 17.3%. This figure is significantly higher (p<0.01) than the 10.8% found in a previous study of subjects born before 1968. This increase is statistically significant in the Center (p<0.01) and in the South (p<0.05) of Italy, but not in the North. Hyperimmunization is not associated with family size (odds ratio 2.16; C. I. 95%=0.5–7.6) or the fathers years of education (odds ratio 1.83; C. I. 95%=0.6–5.3). No difference was found between urban and rural areas of residence. Indiscriminate administration of booster doses of tetanus vaccine in hyperimmune subjects in some areas could result in unnecessary vaccinations, which can cause hypersensitivity reactions.ZusammenfassungIn Italien wurde 1968 die Pflichtimpfung der Kinder gegen Tetanus eingeführt. Bei 17,3% von 214 nach 1968 geborenen Personen mit Tetanus-Immunität wurde eine Hyperimmunisierung (>5 IU/ml) nachgewiesen. Im Vergleich zu einer früheren Studie mit vor 1968 geborenen Personen, bei der sich 10,8% als hyperimmunisiert erwiesen, ist insgesamt ein signifikanter Anstieg (p<0,01) an Hyperimmunisierungen zu verzeichnen. Bei Aufschlüsselung der Daten nach Regionen findet sich eine signifikante Zunahme an Hyperimmunisierungen in Mittel- und Süditalien (p<0,01 bzw. <0,05), aber nicht in Norditalien. Zu der Größe der Familie (Odds ratio=2,16; C. I. 95%=0,5–7,6) oder den Ausbildungsjahren des Vaters (Odds ratio=1,83; C. I. 95%=0,6–5,3) ergaben sich keine Beziehungen. Zwischen der Stadt- und Landbevölkerung waren keine Unterschiede festzustellen. Die undifferenzierte Routine-Auffrischimpfung gegen Tetanus bei bereits voll Immunisierten in manchen Regionen ist unnötig und mit der Gefahr von Überempfindlichkeitsreaktionen verbunden.

Year of birth, sex and residence, as "determinants" of tetanus incidence and immunity in Italy.

Regional results of a seroepidemiological study and official notification data are evaluated to describe the situation of tetanus in Italy. Tetanus incidence has been decreasing during the past years. Vaccination has been the principal means of tetanus prevention. Trend analyses for sex- and age-specific rates suggest a change of exposure, presumably linked to the transformation of the Italian society after the World War II, a higher incidence among the elderly as a function of poor coverage and vanishing immunity. Regional data show remarkable variability in prevalence of susceptible population. Reported rates by region are different. Different degrees of regional underreporting in case notification is suggested.

Tetanus immunity in a partially vaccinated population of children in a district of Naples (Secondigliano)

A general opinion is that compliance with the compulsory immunization programme of children is excellent in Italy.We have studied antitetanus immunity in relation to vaccination history in a sample of 444 school children born between 1977 and 1981 in a district of Naples. Information on vaccination history was collected by interviewing the parents and validated using the official vaccination certificates. Titration of antibodies against tetanus was carried out by the immunoenzymatic method. 0.9% of our study subjects had not been vaccinated at all and only 21.2% had received 4 vaccine doses. In 18 children the presence of antitetanus antibodies was not detected; 14 of them had received one or more doses of vaccine. The lack of compliance with the vaccination programme was associated with a remarkable delay in administering the tetanus vaccine.In the population reported here, the percentage of subjects only partially covered is higher than that found in other regions of Italy.

Prevalence of Chlamydia trachomatis in cases of genital non-gonococcal infection according to microbiological and serological investigations

SummaryAn investigation on the prevalence ofChlamydia trachomatis was carried out on 231 patients (115 men and 116 women, mean age 31.6 years) with genital non-gonococcal infection in order to study the role of this microorganism in infertility and/or sterility in the Italian population. One hundred and sixty-six apparently healthy subjects (108 men and 50 women, mean age 32.4) were also included as control for serological comparison only. Persons with gonococcal infection were excluded. ELISA method was chosen for the directC. trachomatis examination of “scraping” samples. Serological investigations were carried out by means of the indirect immunofluorescence test for IgM and IgG determination as well as the immunoperoxidase assay for IgA antibodies. A directC. trachomatis positive test was demonstrated in 27.8% of men vs. 11.2% in women (p<0.01) in the patient group. Anti-C. trachomatis IgG specific antibodies were present respectively at any serum dilution in 50.2% of patients vs. 47.6% of normal subjects respectively (p >0.5). The low presence ofC. trachomatis (19.5%) at the direct test contrasts with the higher percentage of anti-C. trachomatis positive patients (50.2%) in the same group suggesting that serological tests may be more useful than the direct test in demonstrating an activeC. trachomatis infection provided that IgM, IgG and IgA specific antibodies be contemporaneously investigated.ZusammenfassungZur Erforschung der Bedeutung derChlamydia trachomatis-Infektion als Infertilitäts- und/oder Sterilitätsursache in der italienischen Bevölkerung wurde eine Studie zur Prävalenz dieses Erregers bei 231 Patienten (115 Männer, 116 Frauen, mittleres Alter 31,6 Jahre) mit nicht gonorrhoischer genitaler Infektion durchgeführt. Als Kontrollen für die serologischen Untersuchungen dienten 166 dem Augenschein nach gesunde Personen (108 Männer, 58 Frauen, mittleres Alter 32,4 Jahre). Ausgeschlossen wurden Personen mit Gonokokkeninfektion. Zum Direktnachweis vonC. trachomatis in Abstrichen wurde eine ELISA-Methode eingesetzt. Zur Bestimmung der IgM- und IgG-Antikörper wurde der indirekte Immunfluoreszenztest verwendet, IgA-Antikörper wurden mittels Immunperoxydase-Assay bestimmt.C. trachomatis ließ sich im direkten Nachweisverfahren bei 27,8% Männern und 11,2% Frauen der Patientengruppe nachweisen (p <0,01). Spezifische IgG-Antikörper gegenC. trachomatis fanden sich insgesamt bei 50,2% der Patienten und 47,6% der normalen Kontrollen (p >0,5). Der geringe Anteil im direkten Verfahren positiver Patienten (19,5%) und der erheblich höhere Prozentsatz anti-C. trachomatis positiver Patienten (50,2%) läßt darauf schließen, daß sich die Serologie zum Nachweis einer aktivenC. trachomatis-Infektion besser eignet als der direkte Test, vorausgesetzt spezifische Antikörper der IgM-, IgG- und IgA-Klassen werden gleichzeitig bestimmt.