Selective under-representation of Pacific peoples in population estimates for health indicator measurements in Aotearoa New Zealand misinforms policy making.

BACKGROUND: The Census of Populations and Dwellings' is the five yearly population count of Aotearoa New Zealand. Best available populations (BAP) are subnational projections based on census data and demographic assumptions developed for healthcare planning and funding allocation but are also used as the denominator for health indicator monitoring. Pacific people are systematically undercounted, but the impact on health statistics is not well studied. For COVID-19 vaccination coverage, health service user (HSU) data were considered a more reliable denominator than BAP but introduced new biases. We aimed to understand how the choice of denominator population impacts estimates of population size and health system performance for Pacific people at a local level. METHODS: We described how declining census response rates affected population data quality. We compared BAP and HSU data at district level. For the indicators 'access to primary care' and 'cervical cancer screening uptake' we replaced currently used BAP denominators with HSU and examined the impact for different ethnic groups in different geographic districts. RESULTS: Overall Census 2018 response declined by 10%, but for Maori and Pacific people by 21% and 23%, respectively. This inequitably affected BAP accuracy. Census undercount was highest in the district with the largest Pacific populations, where HSU exceeded BAP most. Notably, 'access to primary care' for Pacific people in this district consistently exceeds 100%. Using BAP, both health indicators are currently estimated as highest for Pacific people compared to other ethnic groups, but when based on HSU, they dropped to lowest. Similar, but less pronounced trends occurred in other districts. Changes in trends over time for both indicators coincided mostly with adjustments in BAP, rather than changes in the numerators. CONCLUSIONS: The current use of BAP denominators for health statistics does not enable reliable monitoring of key health indicators for Pacific people. HSU denominators are also unsuitable for monitoring health. Exploring the feasibility of a real-time population register is strongly recommended as a new, transparent, way of obtaining more reliable, timely population data to guide policymaking and underpin a more equitable health system under the health reforms. Meanwhile, reporting of ethnic specific outcomes need to include a clear assessment of the potential for bias due to inaccurate population estimates.

Sexually Transmitted Infections and the Risk of Reinfection Within 12 Months: A Population-Based Cohort.

BACKGROUND: Chlamydia, gonorrhea, and syphilis are common sexually transmitted infections that disproportionately affect specific groups in New Zealand (NZ). Predictors of reinfection are not well studied in NZ but could inform public health strategies to decrease sexually transmitted infection (STI) incidence. METHODS: New Zealand-wide chlamydia, gonorrhea, and syphilis cases during 2019 were identified using nationally collected data. Cases were followed-up to identify reinfection with the same STI within 12 months of initial infections. Logistic regression models were used to identify predictors for each STI reinfection. RESULTS: Determinants identified for increased odds of chlamydia reinfection were age groups 16-19 and 20-24 years, females, Maori and Pacific peoples, cases in the Northern region, and cases with at least one test before the initial infection. Age 40 years and older was associated with lower odds of gonorrhea reinfection, as was being of Asian ethnicity, living in Midland or Southern regions, and reporting heterosexual behavior. Region was the only statistically significant predictor for syphilis reinfection, with higher odds of reinfection for people living in the Central region. CONCLUSIONS: Our findings reflect disproportionate STI rates for some groups in NZ, with younger age groups, Maori and Pacific peoples, men who have sex with men, and people living in the Northern region experiencing higher odds of reinfection. Groups identified with higher odds for reinfection require increased access to culturally responsive health services to treat, understand, and prevent possible reinfection. Changes to current public health strategies could include culturally specific behavioral counseling, and improvements to and adherence to effective contract tracing.

Invasive Pneumococcal Disease: Concerning Trends in Serotype 19A Notifications in New Zealand.

New Zealand (NZ) is one of few countries to shift from PCV13 to PCV10. The number of serotype 19A cases in young children and the proportions of isolates that are penicillin-resistant have been steadily increasing since. It is time for NZ to reconsider its choice of pneumococcal vaccine.

Airborne Transmission of SARS-CoV-2 Delta Variant within Tightly Monitored Isolation Facility, New Zealand (Aotearoa).

In New Zealand, international arrivals are quarantined and undergo severe acute respiratory syndrome coronavirus 2 screening; those who test positive are transferred to a managed isolation facility (MIF). Solo traveler A and person E from a 5-person travel group (BCDEF) tested positive. After transfer to the MIF, person A and group BCDEF occupied rooms >2 meters apart across a corridor. Persons B, C, and D subsequently tested positive; viral sequences matched A and were distinct from E. The MIF was the only shared location of persons A and B, C, and D, and they had no direct contact. Security camera footage revealed 4 brief episodes of simultaneous door opening during person A's infectious period. This public health investigation demonstrates transmission from A to B, C, and D while in the MIF, with airborne transmission the most plausible explanation. These findings are of global importance for coronavirus disease public health interventions and infection control practices.

Population rates of HIV, gonorrhoea and syphilis diagnoses by sexual orientation in New Zealand.

INTRODUCTION: Globally, gay and bisexual men (GBM) are over-represented in HIV, syphilis and gonorrhoea cases. However, surveillance systems rarely provide meaningful measures of inequity, such as population-specific rates, due to a lack of sexual orientation denominators. HIV, gonorrhoea and syphilis are legally notifiable diseases in New Zealand (NZ); we calculate rates by sexual orientation for the first time. METHODS: We analysed 2019 national surveillance data on HIV, syphilis and gonorrhoea notifications disaggregated by sexual orientation. Unique health records identified duplicate notifications and reinfections. Missing data were imputed from known cases. We used the NZ Health Survey 2014/2015 to estimate population sizes by sexual orientation, measured in two ways (current sexual identity, sexual contact in the previous 12 months with men, women or both). We calculated notification rates per 100 000 for each sexual orientation subgroup and rate ratios. RESULTS: In 2019, GBM accounted for 76.3%, 65.7% and 39.4% of HIV, syphilis and gonorrhoea notifications, respectively. Population rates per 100 000 for HIV were 158.3 (gay/bisexual men) and 0.5 (heterosexuals); for syphilis, population rates per 100 000 were 1231.1 (gay/bisexual men), 5.0 (lesbian/bisexual women) and 7.6 (heterosexuals); for gonorrhoea (imputed), population rates per 100 000 were 6843.2 (gay/bisexual men), 225.1 (lesbian/bisexual women) and 120.9 (heterosexuals). The rate ratios for GBM compared with heterosexuals were: 348.3 (HIV); 162.7 (syphilis); and 56.6 (gonorrhoea). Inequities remained in sensitivity analysis (substituting sexual identity with sexual behaviour in the previous 12 months). CONCLUSION: GBM in NZ experience profound inequities in HIV, syphilis and gonorrhoea. Rate ratios by sexual orientation provide useful 'at-a-glance' measures of inequity in disease incidence.

No chikungunya virus infections among Dutch long-term travellers to (sub)tropical countries: a prospective study 2008-2011.

BACKGROUND: Chikungunya is an arthropod-borne viral disease now identified in over 60 countries in Asia, Africa, Europe, and the Americas. Chikungunya virus (CHIKV) has spread in the last 15 years to many countries, causing large local outbreaks. CHIKV infection can be clinically misdiagnosed in areas where dengue and/or Zika infections occur. Prospective studies are necessary to calculate the true incidence rate of CHIKV infection in travellers. The aim of this study was to obtain the attack and incidence rates of CHIKV infection among long-term travellers and identify associated risk factors. METHODS: A previously collected prospective cohort of Dutch long-term travellers (12-52 weeks) to subtropical and tropical countries was tested. From December 2008 to September 2011, participants were recruited at the travel clinic of the Public Health Service Amsterdam. A weekly diary was kept during travel in which participants recorded their itinerary, symptoms, and physician visits. On return, their pre- and post-travel blood samples were tested for the presence of IgG antibodies to CHIKV antigen. Seroconversions were confirmed by an in-house CHIKV neutralisation test. RESULTS: The median age of 603 participants was 25 years (interquartile range [IQR]: 23-29); 35.7% were male; median travel duration was 20 weeks (IQR: 15-25), and purpose of travel was predominantly tourism (62%). The presence of anti-CHIKV IgG in the pre-travel sample, suggestive of previous CHIKV infection, was found for 3/603 participants (0.5%); all three had been previously travelling in either Africa or Asia. In one traveler who visited Latin America, a seroconversion was found (0.2%) but the CHIKV neutralisation test was negative, making the incidence rate 0. CONCLUSION: No chikungunya virus infections were found in this 2008-2011 prospective cohort of long-term travellers. We recommend the research be repeated, particularly as the sample size of our cohort might have been too small. Also, extensive spread of chikungunya virus has likely increased incidence rates among travellers since 2013.

Hepatitis E in Long-Term Travelers from the Netherlands to Subtropical and Tropical Countries, 2008-2011.

Hepatitis E virus (HEV) is a common cause of acute viral hepatitis. Virus genotypes 1 and 2 infect humans in developing countries by the fecal-oral route. To assess attack rates and disease incidence for travelers, we prospectively studied 604 long-term travelers to subtropical and tropical countries. Participants donated blood samples pretravel and posttravel and kept a diary. A total of 89/604 (15%) pretravel samples were positive for HEV IgG by ELISA, suggesting previous HEV infection. Seroconversion for HEV was found for 19/515 travelers (attack rate 3.7%, incidence 1.8 cases/1,000 person-weeks). We believe there is a substantial risk for acquiring HEV infection among long-term travelers. Although HEV infection does not seem to be a major problem in this healthy cohort, hygienic measures should be stressed in all pretravel health advice, particularly for pregnant women and immunocompromised travelers who are at risk for severe disease.

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) among travellers to Africa: destination-specific data pooled from three European prospective studies.

BACKGROUND: One third of travellers to low- and middle-income regions of the tropics and subtropics become colonized by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). The risk varies by destination and, for each traveller, may be substantially further increased by travellers' diarrhoea (TD) and antibiotic use. Despite the risk of TD in Africa, ESBL-PE acquisition rates in all studies are lower there than in Asia. Africa has become increasingly popular as a destination for international travellers, yet minimal data are available from the continent's subregions and countries. METHODS: We analysed subregion- and country-specific data on carriage and risk factors for ESBL-PE colonization pooled from three prospective studies conducted between 2009 and 2013 among Finnish and Dutch travellers. The data were subjected to multivariable analysis of risk factors. In addition, we compared our data to two recent large investigations reporting data by subregion and country. RESULTS: Our joint analysis comprised data on 396 travellers. The ESBL-PE colonization rate was highest in Northern Africa, followed by Middle and Eastern Africa, and lowest in Southern and Western Africa. Of individual countries with more than 15 visitors, the highest rates were seen for Egypt (12/17; 70.6%), Ghana (6/23; 26.1%), and Tanzania (14/81; 17.3%); the rates among travellers to Egypt were comparable to those reported in South and Southeast Asia. In a pooled multivariable analysis, travel destination, age, overnight hospitalisation abroad, TD, and use of fluoroquinolones were independently associated with increased ESBL-PE colonization rates. CONLUSIONS: Even in areas with relatively low risk of colonization, antimicrobials clearly predispose to colonization with ESBL-PE. Travellers to Africa should be cautioned against unnecessary use of antibiotics.

Determinants of Human Papillomavirus Vaccination Intention Among Female Sex Workers in Amsterdam, the Netherlands.

INTRODUCTION: Female sex workers (FSWs) are at risk for human papillomavirus (HPV)-induced diseases but are currently not targeted by the HPV vaccination program in the Netherlands. We explored determinants of their intention to get vaccinated against HPV in case vaccination would be offered to them. METHODS: In 2016, FSWs 18 years and older having a sexually transmitted infection consultation with the Prostitution & Health Center (P&G292) in Amsterdam, either at the clinic or at their working location, were invited to complete a questionnaire assessing sociopsychological determinants of HPV vaccination intention (scale ranging from -3 to +3). Determinants of HPV vaccination intention were assessed with univariable and multivariable linear regression. In addition, we explored the effect of out-of-pocket payment on intention. RESULTS: Between May and September 2016, 294 FSWs participated. The median age was 29 years (interquartile range, 25-37 years). Human papillomavirus vaccination intention was high (mean, 2.0; 95% confidence interval [CI], 1.8-2.2). In multivariable analysis, attitude (ß = 0.6; 95% CI, 0.5-0.7), descriptive norm (ß = 0.2; 95% CI, 0.1-0.3), self-efficacy (ß = 0.2; 95% CI, 0.1-0.3), beliefs (ß = 0.1; 95% CI, 0.0-0.2), and subjective norm (ß = 0.1; 95% CI, 0.0-0.2) seemed to be the strongest predictors of HPV vaccination intention (R = 0.54). Human papillomavirus vaccination intention decreased significantly to a mean of 0.2 when vaccination would require out-of-pocket payment of &OV0556;350. CONCLUSIONS: The HPV vaccination intention among FSWs seems relatively high and is most strongly constituted in attitudinal, normative, and self-efficacy beliefs. Out-of-pocket payment will probably have a negative impact on their HPV vaccination acceptability.

Increase in imported malaria in the Netherlands in asylum seekers and VFR travellers.

BACKGROUND: Malaria is a notifiable disease in the Netherlands, a non-endemic country. Imported malaria infections occur regularly among travellers, migrants and visitors. Surveillance data were analysed from 2008 to 2015. Trends in amounts of notifications among risk groups were analysed using Poisson regression. For asylum seekers, yearly incidence was calculated per region of origin, using national asylum request statistics as denominator data. For tourists, denominator data were used from travel statistics to estimate incidence per travel region up to 2012. RESULTS: A modest increase in overall imported malaria notifications occurred in 2008-2015 (from 222 in 2008 to 344 in 2015). Notably, in 2014 and 2015 sharp increases were seen in malaria among travellers visiting friends and relatives (VFR), and in asylum seekers. Of all Plasmodium falciparum infections, most (1254/1337; 93.8%) were imported from Africa; 1037/1337 (77.6%) were imported from Central and West Africa. Malaria in VFR was mostly caused by P. falciparum infection after visiting Ghana (22%) or Nigeria (19%). Malaria in asylum seekers was mostly caused by Plasmodium vivax infection from the Horn of Africa. The large number of notifications in asylum seekers resulted from both an increase in number of asylum seekers and a striking increase of malaria incidence in this group. Incidence of malaria in asylum seekers from the Horn of Africa ranged between 0.02 and 0.3% in 2008-2013, but rose to 1.6% in 2014 and 1.3% in 2015. In 2008-2012, incidence in tourists visiting Central and West Africa dropped markedly. CONCLUSIONS: Imported malaria is on the rise again in the Netherlands, most notably since 2013. This is mostly due to immigration of asylum seekers from the Horn of Africa. The predominance of P. vivax infection among asylum seekers warrants vigilance in health workers when a migrant presents with fever, as relapses of this type of malaria can occur long after arrival in the Netherlands.

Influenza in long-term Dutch travelers in the tropics: symptoms and infections.

BACKGROUND: Influenza is a common infection among travelers, and attack rates are well documented in short-term travelers and holiday makers. Little data exists on long-term, non-expatriate travelers. METHODS: This was a prospective mono-centre study of immunocompetent, Dutch travelers aged ≥18 to 64 years. It was conducted at the Public Health Service travel clinic in Amsterdam from December 2008 to September 2011, and included all travelers intending to travel to a tropical or sub-tropical country. RESULTS: Among 602 Dutch long-term travelers to tropical regions, 82 % had protective influenza antibody titres pre-travel. The influenza attack rate of serologically confirmed infection during travel was 15 %, and of symptomatic infection was 6.3 % (fever alone) and 2 % (ILI), respectively. CONCLUSIONS: The attack rate in this study is similar to seasonal rates of infection in the general population. Influenza vaccination pre-travel is therefore most important for people at risk of medical complications due to influenza.

Screening travellers to high-endemic countries for infection with Mycobacterium tuberculosis using interferon gamma release assay; a prospective study.

BACKGROUND: International travel from low-incidence to high-incidence countries for tuberculosis (TB) is regarded as a risk factor for acquiring TB infection. In this prospective study among long-term travellers we examined the incidence of TB infection using Interferon gamma release assay (IGRA) test and compared these data with results from a visit to the TB department to which all long-term travellers were routinely referred. METHODS: Immunocompetent adults, travelling for 13-52 weeks to TB-endemic countries, donated blood pre- and post-travel for IGRA. The pre-travel IGRA was only tested in case of a positive IGRA post-travel. Results from their visit(s) to the TB department for TST pre- and post-travel were collected and compared with study results. RESULTS: We found two IGRA conversions in a group of 516 travellers, resulting in an attack rate (AR) of 0.4% (95% CI: 0.5 - 13.9) and an incidence rate (IR) of 0.85 per 1000 person-months (95% CI: 0.1-3.1).We found 5 tuberculin skin test (TST) conversions, resulting in AR of 1.9% (5/261; 95% CI: 0.6 - 4.4) and an IR of 4.26 per 1000 person-months (95% CI: 1.38- 9.94). In our study these converters all had a negative IGRA. One traveller however, who was retested later at the TB department due to a positive TST, then appeared to have seroconverted. CONCLUSIONS: The risk of long-term travellers among our study population acquiring TB infection is low. We conclude that post-travel IGRA alone could be used for screening for TB infection among long-term travellers to high-endemic TB countries, but preferably not earlier than 8 weeks after return. One might even argue that IGRA testing should be limited to only those travellers who are going to work in a medical setting. A person with a positive IGRA should be referred to a TB physician for further evaluation.

High prevalence of previous dengue virus infection among first-generation Surinamese immigrants in the Netherlands.

BACKGROUND: A substantial portion of Dutch travellers is comprised of immigrants returning to their country of origin to visit friends and relatives (VFRs), including VFRs returning to dengue-endemic areas such as Suriname. Limited attention has been focused on dengue among immigrants, therefore it is unknown whether immigration has effect on the epidemiology of (severe) dengue among VFRs.To get more insight in the seroprevalence of dengue among Surinamese immigrants, we conducted a seroprevalence study on a convenience sample of first-generation Surinamese immigrants living in the Netherlands. METHODS: Blood samples were tested for IgG antibodies to DENV antigen serotypes (1, 2, 3 and 4). Gender, age, years lived in Suriname before immigration, history of yellow fever vaccination, and time between yellow fever vaccination and blood sample collection were examined as possible predictors for previous infection. RESULTS: Of the studied 400 Surinamese travellers with a mean age of 52 years (range 18-89), 37% were male. Serology suggestive of past DENV infection was found in 325 individuals (81.3%; 95% CI: 77-85%). The time lived in Suriname before immigration was the only significant predictor for previous DENV infection. CONCLUSIONS: Most first-generation Surinamese immigrants have evidence of past DENV infection, probably comparable to Surinamese inhabitants. Whether this influences the number of cases of (severe) dengue when travelling requires more study.

Effect of travel on influenza epidemiology.

To assess the attack and incidence rates for influenza virus infections, during October 2006-October 2007 we prospectively studied 1,190 adult short-term travelers from the Netherlands to tropical and subtropical countries. Participants donated blood samples before and after travel and kept a travel diary. The samples were serologically tested for the epidemic strains during the study period. The attack rate for all infections was 7% (86 travelers) and for influenza-like illness (ILI), 0.8%. The incidence rate for all infections was 8.9 per 100 person-months and for ILI, 0.9%. Risk factors for infection were birth in a non-Western country, age 55-64 years, and ILI. In 15 travelers with fever or ILI, influenza virus infection was serologically confirmed; 7 of these travelers were considered contagious or incubating the infection while traveling home. Given the large number of travelers to (sub)tropical countries, travel-related infection most likely contributes to importation and further influenza spread worldwide.

Risk factors for secondary transmission of Shigella infection within households: implications for current prevention policy.

BACKGROUND: Internationally, guidelines to prevent secondary transmission of Shigella infection vary widely. Cases, their contacts with diarrhoea, and those in certain occupational groups are frequently excluded from work, school, or daycare. In the Netherlands, all contacts attending pre-school (age 0-3) and junior classes in primary school (age 4-5), irrespective of symptoms, are also excluded pending microbiological clearance. We identified risk factors for secondary Shigella infection (SSI) within households and evaluated infection control policy in this regard. METHODS: This retrospective cohort study of households where a laboratory confirmed Shigella case was reported in Amsterdam (2002-2009) included all households at high risk for SSI (i.e. any household member under 16 years). Cases were classified as primary, co-primary or SSIs. Using univariable and multivariable binomial regression with clustered robust standard errors to account for household clustering, we examined case and contact factors (Shigella serotype, ethnicity, age, sex, household size, symptoms) associated with SSI in contacts within households. RESULTS: SSI occurred in 25/ 337 contacts (7.4%): 20% were asymptomatic, 68% were female, and median age was 14 years (IQR: 4-38). In a multivariable model adjusted for case and household factors, only diarrhoea in contacts was associated with SSI (IRR 8.0, 95% CI:2.7-23.8). In a second model, factors predictive of SSI in contacts were the age of case (0-3 years (IRRcase≥6 years:2.5, 95% CI:1.1-5.5) and 4-5 years (IRRcase≥6 years:2.2, 95% CI:1.1-4.3)) and household size (>6 persons (IRR2-4 persons 3.4, 95% CI:1.2-9.5)). CONCLUSIONS: To identify symptomatic and asymptomatic SSI, faecal screening should be targeted at all household contacts of preschool cases (0-3 years) and cases attending junior class in primary school (4-5 years) and any household contact with diarrhoea. If screening was limited to these groups, only one asymptomatic adult carrier would have been missed, and potential exclusion of 70 asymptomatic contacts <6 years old from school or daycare, who were contacts of cases of all ages, could have been avoided.

Increased seroprevalence of IgG-class antibodies against cytomegalovirus, parvovirus B19, and varicella-zoster virus in women working in child day care.

BACKGROUND: Primary maternal infection with cytomegalovirus (CMV), parvovirus B19 (B19V), and varicella-zoster virus (VZV) may result in adverse pregnancy outcomes like congenital infection or foetal loss. Women working in child day care have an increased exposure to CMV, B19V, and VZV. By comparing the seroprevalence of IgG-class antibodies against CMV, VZV and B19V in female day care workers (DCW) with the seroprevalence in women not working in day care this study aimed to assess the association between occupation and infection. METHODS: A cross-sectional design was used. Out of a random sample of 266 day care centres, demographic data, data on work history, and blood samples were collected from 285 women from 38 centres. In addition, blood samples and basic demographics from women who participated in a cross-sectional survey of the Amsterdam population (2004) were used. All blood samples were tested for IgG-class antibodies against CMV, B19V, and VZV. RESULTS: Twenty-seven percent of the DCW were still susceptible to B19V or CMV. Working in day care was independently associated with B19V infection in all DCW (prevalence ratio [PR] 1.2; 95 % CI 1.1-1.3), and with CMV infection in DCW of European origin only (PR 1.7; 95 % CI 1.3-2.3). Almost all women born outside Europe tested seropositive for CMV (96 %). All DCW tested seropositive for VZV, compared to only 94 % of the women not working in day care. CONCLUSION: This study confirms the clear association between employment in child day care centres and infection with CMV and B19V. Intervention policies, like screening of new employees and awareness campaigns emphasizing hygienic measures among DCW, should be implemented urgently to improve the maternal health of these women and the health of their offspring.

Malaria in long-term travelers: Infection risks and adherence to preventive measures - A prospective cohort study.

BACKGROUND: Chemoprophylaxis and anti-mosquito measures are key to preventing malaria in travelers. Long-term travelers are at higher risk than short-term travelers, but their adherence to preventive measures is lower. Our aim was to determine malaria exposure risks and predictors for adherence to malaria-preventive measures in long-term travelers. METHODS: Long-term travelers (>12 weeks) completed a weekly questionnaire about preventive measures, symptoms, and malaria treatment abroad. Blood samples were tested for seroconversion to Plasmodium falciparum anti-circumsporozoite (PfCSP) antibody. Adherence to preventive measures was defined as number of weeks of their usage divided by number of weeks in malaria-endemic areas. RESULTS: Of 561 travelers, the median travel time was 20 weeks (IQR 16-25). Eighteen were treated for malaria, all in sub-Saharan Africa. Sixteen PfCSP seroconversions were found, of whom only 3 had traveled to high-endemic areas. Of the 18 travelers treated for malaria, only one seroconverted. No associations were found between covariates and seroconversion. Neither treatment abroad nor seroconversion were reliable predictors for exposure. 'Full adherence' to chemoprophylaxis was reported by 52% (218/417) and was associated with travel to Africa, use of mefloquine, lack of prior travel history, shorter duration of travel, and use of DEET. CONCLUSIONS: The risk of malaria in this long-term travelers cohort was low. Our data confirm that anti-PfCSP seroconversion is not a reliable method to retrospectively identify incident infection, or probably exposure. Prevention efforts should focus on more experienced travellers and longer travel duration, for whom mefloquine should be considered as the first-choice chemoprophylaxis.

Travel-related dengue virus infection, The Netherlands, 2006-2007.

To assess the incidence of and risk factors for clinical and subclinical dengue virus (DENV) infection, we prospectively studied 1,207 adult short-term travelers from the Netherlands to dengue-endemic areas. Participants donated blood samples for serologic testing before and after travel. Blood samples were tested for antibodies against DENV. Seroconversion occurred in 14 (1.2%) travelers at risk. The incidence rate was 14.6 per 1,000 person-months. The incidence rate was significantly higher for travel during the rainy months. Dengue-like illness occurred in 5 of the 14 travelers who seroconverted. Seroconversion was significantly related to fever, retro-orbital pain, myalgia, arthralgia, and skin rash. The risk for DENV infection for short-term travelers to dengue-endemic areas is substantial. The incidence rate for this study is comparable with that in 2 other serology-based prospective studies conducted in the 1990s.

Comparison of two HIV postexposure prophylaxis regimens among men who have sex with men in Amsterdam: adverse effects do not influence compliance.

OBJECTIVES: To compare 2 regimens for HIV postexposure prophylaxis (PEP) as to safety, adherence, outcome, and follow-up in men who have sex with men (MSM) in Amsterdam. METHODS: Since 2000, all MSM starting HIV PEP in Amsterdam have been followed in 1 location. The regimen was comprised of zidovudine or lamivudine and nelfinavir (regimen 1) until 2005, when nelfinavir was replaced by atazanavir (regimen 2). All patient data, including data on PEP side effects and testing for alanine aminotransferase (ALT), were systematically recorded and compared between the 2 regimens from 2000 to 2007. RESULTS: HIV PEP was prescribed 309 times to MSM. Of the 261 who were followed up, 237 (91%) completed their 28-day course. Although fewer patients had diarrhea on regimen 2 than on regimen 1 (P = 0.00), the proportion completing either course was the same: 98 of 110 (89%) and 139 of 151 (92%), respectively (P = 0.42). Only 1 patient with severely elevated ALT was advised to stop PEP, he also had serious illness. MSM at least 30 years of age and MSM who had sex with a partner known to be HIV-positive completed their course significantly more often than those under 30 and those who had sex with a partner of unknown HIV status (P < 0.005). Of MSM who completed PEP, 5 seroconverted for HIV despite good adherence to PEP. None of their viruses were resistant to the PEP regimen used. CONCLUSIONS: No difference in adherence was found between the 2 regimens, even though fewer adverse effects were reported on regimen 2. ALT need not be routinely tested to monitor adverse effects. The 5 seroconversions were not likely caused by PEP failure, but rather by ongoing HIV exposures.

Declining incidence of imported malaria in the Netherlands, 2000-2007.

BACKGROUND: To describe the epidemiology and trends of imported malaria in the Netherlands from 2000 through 2007. METHODS: Based on national surveillance data regarding all reported infections of imported malaria, diagnosed 2000 through 2007, incidence and trends of imported malaria in the Netherlands were estimated. Travellers statistics were used to estimate incidence, and data on malaria chemoprophylaxis prescriptions were used to estimate the number of unprotected travellers. RESULTS: Importation of malaria to the Netherlands is declining even as more travellers visit malaria-endemic countries. On average, 82% were acquired in sub-Saharan Africa, and 75% were caused by Plasmodium falciparum. The overall incidence in imported falciparum malaria fell from 21.5 to 6.6/10,000 of unprotected travellers. The percentage of unprotected travellers rose from 47% to 52% of all travellers. The incidence of imported falciparum infections is greatest from Middle and West Africa, and decreased from 121.3 to 36.5/10,000 travellers. The import of malaria from this region by immigrants visiting friends and relatives (VFR) decreased from 138 infections in 2000, to 69 infections in 2007. CONCLUSION: The annual number of imported malaria shows a continuing declining trend, even with an increasing number of travellers visiting malaria endemic countries. VFR import less malaria than previously, and contribute largely to the declining incidence seen. The decline is not readily explained by increased use of chemoprophylaxis and may reflect a reduced risk of infection due to decreasing local malaria transmission as observed in some malaria endemic areas. Nevertheless, the increasing number of unprotected travellers remains worrisome.