Helena H. Askling

Malaria risk in travelers.

Malaria risk around the world was assessed by using Swedish surveillance data from 1997 to 2003 with an extensive travel database as denominator.

Management of imported malaria in Europe

In this position paper, the European Society for Clinical Microbiology and Infectious Diseases, Study Group on Clinical Parasitology, summarizes main issues regarding the management of imported malaria cases. Malaria is a rare diagnosis in Europe, but it is a medical emergency. A travel history is the key to suspecting malaria and is mandatory in patients with fever. There are no specific clinical signs or symptoms of malaria although fever is seen in almost all non-immune patients. Migrants from malaria endemic areas may have few symptoms.Malaria diagnostics should be performed immediately on suspicion of malaria and the gold- standard is microscopy of Giemsa-stained thick and thin blood films. A Rapid Diagnostic Test (RDT) may be used as an initial screening tool, but does not replace urgent microscopy which should be done in parallel. Delays in microscopy, however, should not lead to delayed initiation of appropriate treatment. Patients diagnosed with malaria should usually be hospitalized. If outpatient management is preferred, as is the practice in some European centres, patients must usually be followed closely (at least daily) until clinical and parasitological cure. Treatment of uncomplicated Plasmodium falciparum malaria is either with oral artemisinin combination therapy (ACT) or with the combination atovaquone/proguanil. Two forms of ACT are available in Europe: artemether/lumefantrine and dihydroartemisinin/piperaquine. ACT is also effective against Plasmodium vivax, Plasmodium ovale, Plasmodium malariae and Plasmodium knowlesi, but these species can be treated with chloroquine. Treatment of persistent liver forms in P. vivax and P. ovale with primaquine is indicated after excluding glucose 6 phosphate dehydrogenase deficiency. There are modified schedules and drug options for the treatment of malaria in special patient groups, such as children and pregnant women. The potential for drug interactions and the role of food in the absorption of anti-malarials are important considerations in the choice of treatment.Complicated malaria is treated with intravenous artesunate resulting in a much more rapid decrease in parasite density compared to quinine. Patients treated with intravenous artesunate should be closely monitored for haemolysis for four weeks after treatment. There is a concern in some countries about the lack of artesunate produced according to Good Manufacturing Practice (GMP).

Hepatitis A Risk in Travelers

BACKGROUND Traveling to highly endemic areas for hepatitis A is increasing while the immunization level in travelers has been shown to be low in the countries studied. METHODS In this population-based study, we have estimated the incidence rate of travel-related hepatitis A during 1997 to 2005 by use of the Swedish notification system of communicable diseases and an ongoing national database on travel patterns. We have also acquired airport-based immunization data from 2007. RESULTS During the study period, 636 cases of travel-related hepatitis A were notified. Traveling to East Africa was associated with the highest incidence rate (14.1 cases/100,000 person months), followed by the Middle East (5.8/100,000 person months), and India with neighboring countries (5.6/100,000 person months). Visiting Friends and Relatives (VFR) travelers represented 83, 91, and 70% of the cases to these three regions. By age-group, the highest incidence was found in children 0 to 14 years (3.1/100,000 travelers) where 88% of the cases were VFR travelers. Incidence rate in unprotected travelers to East Asia, North Africa, and the Middle East was 2, 12, and 18 cases/100,000 person months, respectively. In 2007, 79% of the travelers were immunized against hepatitis A. CONCLUSIONS We conclude that travelers, and especially children, who are VFR in endemic areas constitute a high-risk group for acquiring hepatitis A infection, while the risk for unprotected tourists to East Asia is low.

Cross-Protective Capacity of Japanese Encephalitis (JE) Vaccines Against Circulating Heterologous JE Virus Genotypes

Current Japanese encephalitis vaccines are derived from strains of genotype III, yet heterologous genotypes are emerging in endemic areas. Inactivated vaccines given to European travelers were found to elicit protective levels of neutralizing antibodies against heterologous strains of genotypes I–IV.

Hepatitis A vaccine for immunosuppressed patients with rheumatoid arthritis: A prospective, open-label, multi-centre study☆☆

BACKGROUND Hepatitis A vaccine is the most frequently used travel vaccine, yet data are scarce about its ability to induce protection in patients with concurrent immunosuppressive treatment. We assessed the immunogenicity of this vaccine in rheumatoid arthritis (RA) patients treated with tumour necrosis factor-inhibitors (TNFi) and/or methotrexate (MTX). METHODS Hepatitis A vaccine was administered to non-immune RA patients at 0 and 6 months. Hepatitis A virus (HAV) antibodies were assessed at 0, 1, 6, 7, 12, and 24 months with a quantitative Chemiluminescent Microparticle Immuno Assay (CMIA) for HAV-IgG. Samples from month 1, 6, and 7 were, in addition, analysed with a microparticle EIA (MEIA) for anti-HAV IgM + IgG. RESULTS The final study population consisted of 53 patients treated with TNFi (n = 15), TNFi + MTX (n = 21) or MTX (n = 17). One and six months after the first dose, 10% and 33% of the patients had attained seroprotection. One and six months after the second dose 83% and 72% were seroprotected. At month 24, 86% of the vaccinees showed protective levels. CONCLUSIONS Two doses of hepatitis A vaccine at a 6-month interval provided protection for most immunosuppressed RA patients. A single dose does not seem to afford sufficient protection to this group of patients.

A Single Dose of Vero Cell–Derived Japanese Encephalitis (JE) Vaccine (Ixiaro) Effectively Boosts Immunity in Travelers Primed With Mouse Brain–Derived JE Vaccines

The new Japanese encephalitis vaccine (JE-VC, Ixiaro) has replaced mouse brain–derived vaccines (JE-MB) associated with serious safety concerns. A single dose of JE-VC effectively boosted immunity in JE-MB–primed travelers. Current recommendations for booster vaccination should be reevaluated.

Serologic Analysis of Returned Travelers with Fever, Sweden

We studied 1,432 febrile travelers from Sweden who had returned from malaria-endemic areas during March 2005–March 2008. In 383 patients, paired serum samples were blindly analyzed for influenza and 7 other agents. For 21% of 115 patients with fever of unknown origin, serologic analysis showed that influenza was the major cause.

The medically immunocompromised adult traveler and pre-travel counseling: status quo 2014.

International travel is increasing among a growing number of medically immunosuppressed patients regaining life-activity due to efficient drugs. Adequate pre-travel advice for this group of patients requires not only a travel-medicine expert but a relevant specialist as well, so that a personalized plan can be made concerning vaccinations and other prophylaxis. Inactivated vaccines can generally be prescribed during immunosuppressive therapy; the risk of inducing an exacerbation of the underlying disease is minimal and even though the post-vaccination antibody response will often be impaired, it will possibly benefit the patient by means of inducing a milder course of the disease. Live vaccines are generally contraindicated and if the risk of getting the disease in a particular country is high, the potential risks must be carefully discussed with the patient. It is essential to try to prevent infections in this group of patients who are more vulnerable to serious complications caused by the immunosuppression. The aim of this review was to summarize the available literature on immunosuppressive drug mechanisms and evidence on pre-travel-vaccinations, malaria prophylaxis as well as drugs preventing tourist diarrhea. The immunocompromised conditions/drugs used in these conditions that are covered include solid organ transplantations (SOT), hematopoietic stem cell transplantations, splenectomy, and chronic inflammatory diseases in adults. HIV and pediatric patient populations are not included.

Influenza in travellers.

Purpose of review The importance of travelling as an important factor for spread of influenza has become even more evident during the recent pandemic year. All the same, the mechanism for seasonal spreading of influenza is not yet fully understood. Recent findings The incidence of influenza in returning febrile travellers from subtropical and tropical regions is between 5 and 15% with no significant differences between those vaccinated and not vaccinated in the reviewed studies. The power of the studies to detect differences are, however, low. In these studies, 12–85% of the travellers or pilgrims were vaccinated against influenza. Air transportation, and especially long-haul flight, is a key factor for the spread of influenza even though travel restrictions seem to be of no use for preventing a pandemic spread. Summary Influenza should always be considered in a febrile traveller with or without respiratory symptoms. Future studies on incidence of travel-related influenza should consider the short incubation period for a better estimate. Vaccine from the opposite hemisphere should be made available for travellers, and influenza vaccine studies should focus on optimizing the effect of the vaccine in the elderly and immunocompromised.

Tick borne encephalitis (TBE)-vaccination coverage and analysis of variables associated with vaccination, Sweden

To estimate the tick borne encephalitis (TBE)-vaccination coverage in the greater Stockholm region, we sent a questionnaire to a randomized sample of 8000 individuals in 2013. Fifty-three percent of all respondents (n=4307) reported being vaccinated against TBE at least once. Reasons for not vaccinating included: no perceived risk (28.6%), too expensive (25.6%), did not have the time or opportunity (23%) and worried about vaccine side-effects (20.5%). Multiple logistic regression revealed that the probability of being vaccinated was higher among those who reported ≥2 weeks outdoor exposure in a known high risk area (OR 4.13 95% CI 3.54-4.81) and in individuals ≥60 years of age compared to all other age groups (OR 0.67 95% CI 0.55-0.81). A high net household income was associated with a higher probability of being vaccinated (OR 2.10 95% CI 1.6-2.73). Being born outside Europe was negatively correlated (OR 0.57 95% CI 0.39-0.83). Based on our findings the estimated TBE-incidence in the unvaccinated regional population was 8.5-12/100,000 which is comparable with high endemic areas as the Baltic region and Central Europe. We suggest targeted vaccination and reimbursement strategies in high-endemic areas of Sweden. Our results indicate a need for improved public information about TBE.