Syphilis epidemiology in Sweden: re-emergence since 2000 primarily due to spread among men who have sex with men.

Syphilis has re-emerged in western Europe since 2000. Changes in sexual behaviour have facilitated the spread of syphilis especially among men who have sex with men (MSM) and improved surveillance systems and case detection have lead to an increase in the reported numbers of cases. This report describes recent trends (2000-2007) of syphilis in Sweden, where the spread among MSM, particularly in the big cities, has been a major contributor to an increase in cases. Estimated syphilis incidence among MSM was up to twenty-eight times higher than in the general Swedish male population. The most affected age group among males was 25-44 years of age. The majority of infections in men and women through heterosexual contacts were acquired abroad whereas the majority of infections attributed to sex between men were acquired in Sweden. Appropriate prevention activities are needed to reach vulnerable populations in Sweden.

SmiNet-2: Description of an internet-based surveillance system for communicable diseases in Sweden.

Electronic systems for communicable diseases surveillance enhance quality by simplifying reporting, improving completeness, and increasing timeliness. In this article we outline the ideas and technologies behind SmiNet-2, a new comprehensive regional/national system for communicable disease surveillance in Sweden. The system allows for reporting from physicians (web form) and laboratories (direct from lab data system) over the internet. Using a unique personal identification number, SmiNet-2 automatically merges clinical and laboratory notifications to case records. Privileged users, at national and county level, work against a common central server containing all notifications and case records. In addition, SmiNet-2 has separate county servers with tools for outbreak investigations, contact tracing and case management. SmiNet-2 was first used in September 2004. Individual counties receive up to 90% of all notifications electronically. In its first year, SmiNet-2 received 54 980 clinical notifications and 32,765 laboratory notifications, which generated 58,891 case records. Since most clinicians in Sweden have easy access to the internet, a general web-based reporting has been feasible, and it is anticipated that within a few years all reporting to SmiNet-2 will be over the internet. In this context, some of the major advantages of SmiNet-2 when compared with other systems are timeliness in the dataflow (up to national level), the full integration of clinical and laboratory notifications, and the capability to handle more than 50 diseases with tailor-made notification forms within one single system.

SmiNet-2: Description of an internet-based surveillance system for communicable diseases in Sweden.

Electronic systems for communicable diseases surveillance enhance quality by simplifying reporting, improving completeness, and increasing timeliness. In this article we outline the ideas and technologies behind SmiNet-2, a new comprehensive regional/national system for communicable disease surveillance in Sweden. The system allows for reporting from physicians (web form) and laboratories (direct from lab data system) over the internet. Using a unique personal identification number, SmiNet-2 automatically merges clinical and laboratory notifications to case records. Privileged users, at national and county level, work against a common central server containing all notifications and case records. In addition, SmiNet-2 has separate county servers with tools for outbreak investigations, contact tracing and case management. SmiNet-2 was first used in September 2004. Individual counties receive up to 90% of all notifications electronically. In its first year, SmiNet-2 received 54 980 clinical notifications and 32 765 laboratory notifications, which generated 58 891 case records. Since most clinicians in Sweden have easy access to the internet, a general web-based reporting has been feasible, and it is anticipated that within a few years all reporting to SmiNet-2 will be over the internet. In this context, some of the major advantages of SmiNet-2 when compared with other systems are timeliness in the dataflow (up to national level), the full integration of clinical and laboratory notifications, and the capability to handle more than 50 diseases with tailor-made notification forms within one single system.

An outbreak of mumps in Sweden, February-April 2004.

Between 24 February and 26 April 2004, Västra Götaland county in Sweden reported 42 cases of suspected mumps. A descriptive study of the cases was undertaken. A questionnaire was administered by telephone and vaccine effectiveness was calculated using the screening method. Seventy four per cent (31/42) of the suspected cases were interviewed by telephone. Eight out of the 42 serum samples were positive or equivocal for mumps IgM by ELISA. Mumps virus genome was identified in 21/42 (50%) saliva samples. Eleven were selected for sequencing and all were confirmed to be mumps virus. Cases were predominantly from 2 small towns. Eighteen out of 19 cases that developed bilateral swelling could be linked to one small town. The median age of interviewed cases was 43 years (range 5 to 88). Six cases were admitted to hospital, 5 of which were older than 30 years. The highest incidence occurred in the 35 to 44 years age group. Vaccine effectiveness was estimated to be 65% for 1 dose and 91% for 2 doses. This descriptive study shows the increasing age of mumps cases with increasing vaccine coverage. Vaccine effectiveness was particularly high for 2 doses. Second-dose uptake must be ensured, as primary vaccine failure is well documented in mumps. Stronger precautions must be taken to avoid pools of susceptible older individuals accumulating due to the increased risk of complications.

Patients unaware of their HIV infection until AIDS diagnosis in Sweden 1996-2002--a remaining problem in the highly active antiretroviral therapy era.

Our objective was to analyse the characteristics of patients who were unaware of their HIV infection until they developed AIDS, in the period after introduction of highly active antiretroviral therapy. The complete national register of HIV and AIDS cases reported to the Department of Epidemiology at the Swedish Institute for Infectious Disease Control 1996-2002 was searched for cases diagnosed with HIV less than three months before AIDS diagnosis (so-called "late testers"). Of a total of 487 patients with AIDS, reported during the seven-year period, 219 (45%) were late testers. Their proportion of all AIDS cases increased from 22% in 1996 to 58% in 2002. Heterosexual route of transmission, age greater than 40 years, and foreign origin were all significant risk factors for being a late tester. Intravenous drug users were associated with a highly significant reduced risk. The group without previously known HIV infection represents an increasing part of all cases of AIDS. From a disease control and from a medical perspective, it is important to study this group further and discover what measures are needed for earlier identification and access to medical care.

Sensitivity of the Swedish statutory surveillance system for communicable diseases 1998-2002, assessed by the capture-recapture method.

To assess the sensitivity of the Swedish surveillance system, four notifiable communicable diseases in Sweden were examined during 1998-2002 with the two-sources capture-recapture method, based on parallel clinical and laboratory notifications. The sensitivity (proportion of diagnosed diseases actually being notified) was highest for salmonellosis (99.9%), followed by meningococcal infection (98.7%), and tularaemia (98.5%). For penicillin-resistant pneumococci, introduced as a notifiable disease in 1996, the overall sensitivity was 93.4%--increasing from 86.5% in 1998 to 98.5% in 2002. The system benefited from parallel reporting, with a sensitivity of clinical and laboratory notifications alone (all diseases combined) of 91.6% and 95.9% respectively. The sensitivity of both clinical and laboratory notifications was markedly higher in counties using the national electronic reporting system, SmiNet. Thus, sensitivity was higher for diseases with a long tradition of reporting, and there is a run-in period after a new disease becomes notifiable.

An outbreak of mumps in Sweden, February-April 2004.

Between 24 February and 26 April 2004, Västra Götaland county in Sweden reported 42 cases of suspected mumps. A descriptive study of the cases was undertaken. A questionnaire was administered by telephone and vaccine effectiveness was calculated using the screening method. Seventy four per cent (31/42) of the suspected cases were interviewed by telephone. Eight out of the 42 serum samples were positive or equivocal for mumps IgM by ELISA. Mumps virus genome was identified in 21/42 (50%) saliva samples. Eleven were selected for sequencing and all were confirmed to be mumps virus. Cases were predominantly from 2 small towns. Eighteen out of 19 cases that developed bilateral swelling could be linked to one small town. The median age of interviewed cases was 43 years (range 5 to 88). Six cases were admitted to hospital, 5 of which were older than 30 years. The highest incidence occurred in the 35 to 44 years age group. Vaccine effectiveness was estimated to be 65% for 1 dose and 91% for 2 doses. This descriptive study shows the increasing age of mumps cases with increasing vaccine coverage. Vaccine effectiveness was particularly high for 2 doses. Second-dose uptake must be ensured, as primary vaccine failure is well documented in mumps. Stronger precautions must be taken to avoid pools of susceptible older individuals accumulating due to the increased risk of complications.

Febrile gastroenteritis after eating on-farm manufactured fresh cheese--an outbreak of listeriosis?

An outbreak of febrile gastroenteritis affected consumers of on-farm manufactured dairy products from a summer farm in Sweden. Symptoms included diarrhoea, fever, stomach cramps and vomiting in 88, 60, 54 and 21% of cases identified. The median incubation period was 31 h. A cohort study with 33 consumers showed an attack rate of 52% and an association between the total amount of product eaten and illness (P=0.07). Twenty-seven of 32 (84%) stool samples cultured for Listeria monocytogenes tested positive, although there was no association between clinical disease and the isolation of L. monocytogenes. In addition, gene sequences for VTEC and ETEC were detected in 6 and 1 subjects, respectively. Bacteriological analysis of cheese samples revealed heavy contamination with L. monocytogenes and coagulase positive staphylococci in all of them and gene markers for VTEC in one of them. Molecular profiles for L. monocytogenes isolated from dairy products, stool samples and an abscess from 1 patient who developed septic arthritis were identical. Results of both microbiological and epidemiological analyses point to L. monocytogenes as the most likely cause of this outbreak. The finding of markers for VTEC in some humans and cheese samples means that a mixed aetiology at least in some cases cannot be conclusively ruled out.

Back-calculation based on HIV and AIDS registers in Denmark, Norway and Sweden 1977-95 among homosexual men: estimation of absolute rates, incidence rates and prevalence of HIV.

BACKGROUND: The Scandinavian countries, Denmark, Norway and Sweden, have established both HIV and AIDS registers to monitor the HIV epidemic. Information in such registers can be used to estimate the number of new HIV infections over time, incidence rates and prevalence. Information from the HIV registers made it possible to study what kind of effects such information had in the estimation process, compared with using information about new AIDS cases only. METHODS: A Markov model back-calculation approach was used. One model incorporated data on cases of both HIV and AIDS. Another model incorporated data on cases of AIDS only. Death or emigration prior to the onset of AIDS and effects of treatment were included in both models. RESULTS: Estimates of absolute rates of HIV for men who have sex with men (MSM) showed a distinct development in each country. Significant differences in incidence rates and prevalence of HIV among MSM were found between Scandinavian countries when information on diagnosed HIV was incorporated. Precision was improved when using both HIV and AIDS diagnosed cases compared with using AIDS cases only. The epidemic in Denmark was more extensive than in the two other countries for the whole study period. DISCUSSION: The results were fairly robust against reasonable variation in the model parameters. The more extensive epidemic in Denmark may have been caused by the homosexual culture denying that HIV was a disease more relevant to them than to others, until the HIV test was publicly available in 1985.

Immunity to measles before and after MMR booster or primary vaccination at 12 years of age in the first generation offered the 2-dose immunization programme.

In 1982, a 2-dose regimen was introduced in Sweden for the combined vaccination against measles, mumps and rubella (MMR) in children aged 18 months and 12 years. In 1993, blood samples from 378 12-year-old children, i.e. the first age-group receiving a MMR booster, were collected prior to and 2 months after the vaccination. 82% had a certificate of a previous measles (M) or MMR vaccination (group I). The remainder was classified as children with 'no documentation' (group II). In group I, 5 (1.5%) lacked demonstrable antibodies to measles prior to the booster; in group II this figure was 39%. The pre-booster antibody pattern was similar in M vaccinees and MMR vaccinees. After the vaccination, 1 of the 378 children was seronegative. In both groups, children with low pre-vaccination levels responded with a titre rise, in accordance with a similar study 6 years earlier.

Screening for human T cell leukaemia/lymphoma virus among blood donors in Sweden: cost effectiveness analysis.

OBJECTIVE: To analyse the cost effectiveness of a national programme to screen blood donors for infection with the human T cell leukaemia/lymphoma virus. DESIGN: Three models for calculating the costs and benefits of screening were developed. The first model analysed the cost of continuously testing all donations; the second analysed the cost of initially testing new blood donors and then retesting them after five years; the third analysed the cost of testing donors only at the time of their first donation. Patients who had received blood components from donors confirmed to be infected with the virus were offered testing. SETTING: Sweden. MAIN OUTCOME MEASURES: Prevalence of infection with the virus among blood donors, the risk of transmission of the virus, screening costs, and the outcome of infection. RESULTS: 648 497 donations were tested for the virus; 1625 samples tested positive by enzyme linked immunosorbent assay. 6 were confirmed positive by western blotting. The prevalence of infection with the virus was 2/100 000 donors. 35 patients who had received blood infected with the virus were tested; 3 were positive. The cost of testing every donation was calculated to be $3.02m (1.88m pounds); this is 18 times higher than the cost of testing new donors only, and only 1 additional positive donor would be discovered in 7 years. Regardless of the model used, screening was estimated to prevent only 1 death every 200 years at a minimum cost of $36m (22.5m pounds). CONCLUSION: Based on these estimates the Swedish National Board of Health and Welfare decided that only new blood donors would be screened for infection with the virus.

Immunity to mumps before and after MMR vaccination at 12 years of age in the first generation offered the two-dose immunization programme.

Sweden was the first country in the world to introduce a two-dose programme of vaccination against measles, mumps and rubella with a combined vaccine (MMR). It was commenced in 1982 and the vaccination was carried out at the ages of 18 months and 12 years. In 1992-93 the first age-group vaccinated at 18 months reached the age of 12 and accordingly received a second dose of MMR. A total of 382 children participated in the present study. Sero-immunity against mumps was studied by testing neutralizing antibodies using serial dilutions inoculated into cell cultures before and after the 12-year vaccination. Of the 229 children earlier vaccinated (group A), 27% lacked demonstrable antibodies before the booster. Of those without documented vaccination records (group B), 56% were seronegative before vaccination. After vaccination, 93% of group A and 86% of group B were seropositive (titre > or = 2). In the seronegative children, whether vaccinated earlier or not, the seroconversion was ca 75%. Previously unvaccinated children positive before vaccination and thus likely to be naturally immune had a higher mean-titre both before and after vaccination than the seropositive children earlier vaccinated. So far, the two-dose programme has proceeded as expected.

[The year of the world aids day: children in a world of AIDS]. / Arets världsaidsdag: barn i en värld med aids.

PIP: "Children living in a world with AIDS" was the theme of a UNAIDS campaign launched because 1 million children are infected with HIV and 9 million children have become orphans due to AIDS (90% in sub-Saharan Africa). During 1996 alone, 400,000 children were infected: 90% were infected during pregnancy, delivery, or while breast feeding; the remaining 10% were infected sexually or via blood or blood products. In Africa, only one-third of HIV-infected children survive their 3rd birthday, and 8% of all children in Zimbabwe have lost their mothers to AIDS. A similar situation is rapidly evolving in Asia and South America. In Spain and Italy, more than 600 children have AIDS; most of them were infected through drug-abusing mothers. In France the figure is comparable, but here a large segment is represented by children of mothers from African countries. The total number of children with AIDS in the European Community is 2800: 86% were infected through their mothers. Romania has 4000 children with AIDS, who were predominantly infected via nonsterile syringes and blood transfusion. The European Commission has a specific AIDS prevention program, which addresses the measurement of disease spread, counteracting the disease, information and education, support for persons with HIV/AIDS, and countering discrimination. The risk of mother-to-child HIV transmission can be reduced from 25% to 8% by zidovudine (AZT) treatment during pregnancy and delivery.^ieng

Screening for HIV-1 antibodies in pregnancy: results from the Swedish national programme.

OBJECTIVE: To determine the effectiveness of a national screening programme for HIV infection in pregnant women. DESIGN: Observational study. SUBJECTS: All pregnant women presenting to antenatal or abortion clinics. SETTING: Sweden, September 1987 to December 1991. MAIN OUTCOME MEASURES: Number and characteristics of infected women. RESULTS: By the end of the study period 510,000 tests had been performed and 54 women with HIV infection identified (1.06/10,000). Of the 33 women identified in Stockholm, 14 women (4.4/10,000) had attended abortion clinics and 19 antenatal clinics (1.8/10,000; p < 0.05). Three women had been intravenous drug users, one was infected through a blood transfusion, and 50 were probably infected sexually. Of the 20 women who attended antenatal clinics early enough to allow an abortion, 12 continued with their pregnancies. CONCLUSIONS: Testing of all women, not just those perceived to be at risk, probably contributed to the high uptake of HIV testing. With high uptake such screening provides valuable data on spread of HIV in the heterosexual population and presents opportunity for preventing transmission of HIV to children and partners.

Evaluation of HIV testing in Sweden, 1985-1991.

OBJECTIVE: Evaluation of the extent and outcome of HIV testing in Sweden. DESIGN: Data from screening programmes, laboratory and clinical reports were compared and a national survey on HIV testing was performed. RESULTS: The proportion found to be positive in screening of blood donors, pregnant women and sexually transmitted disease patients were approximately 1/100,000, 1/10,000 and 1-2/1000, respectively. One-quarter of the men and one-third of the women in Sweden aged 16-74 years reported that they had been tested for HIV at least once. CONCLUSION: There is a high cost involved in detecting HIV-infected individuals through general testing. This cost can be justified if we believe that awareness of an infection substantially reduces the risk of further transmission.