Malaria chemoprophylaxis in UK general practitioners traveling to South Asia

A systematic review of factors affecting adherence to malaria chemoprophylaxis amongst travellers from non-endemic countries

Background

The aim of this systematic review was to identify predictors of actual or intended adherence with malaria chemoprophylaxis amongst travellers from non-endemic countries visiting endemic countries.

Methods

A systematic review of the literature was conducted using MEDLINE, Embase, PsycINFO and Global Health databases for studies published up to April 2019. Studies were included if they assessed reasons for adherence among people travelling from a country where malaria was not endemic to a country where it was.

Results

Thirty-two studies were included. Predictors of adherence were categorized as relating to either the nature of the travel or the traveller themselves. The three main predictors associated with nature of travel included: destination (e.g. country visited, urban vs rural areas), length of travel and type of travel (e.g. package vs backpacking holiday). The four main traveller-associated predictors were: age, reason for travel (e.g. business, leisure or visiting friends and relatives), perceived risk of catching malaria and experienced or expected medication effects.

Conclusions

In order to improve adherence, clinicians should focus on travellers who are least likely to exhibit adherent behaviour. This includes travellers visiting destinations known to have lower adherence figures (such as rural areas), backpackers, business travellers, younger travellers and those travelling for longer periods of time. They should also check to ensure travellers’ perceptions of the risks of malaria are realistic. Where appropriate, misperceptions (such as believing that curing malaria is easier than taking prophylaxis or that travellers visiting relatives have some level of innate immunity) should be corrected. All travellers should be informed of the potential side-effects of medication and given guidance on why it is nonetheless beneficial to continue to take prophylaxis. Further research is required to test interventions to improve adherence.

Mefloquine for preventing malaria during travel to endemic areas

BACKGROUND

Mefloquine is one of four antimalarial agents commonly recommended for preventing malaria in travellers to malaria-endemic areas. Despite its high efficacy, there is controversy about its psychological side effects.

OBJECTIVES

To summarize the efficacy and safety of mefloquine used as prophylaxis for malaria in travellers.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published on the Cochrane Library; MEDLINE; Embase (OVID); TOXLINE (https://toxnet.nlm.nih.gov/newtoxnet/toxline.htm); and LILACS. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP; http://www.who.int/ictrp/en/) and ClinicalTrials.gov (https://clinicaltrials.gov/ct2/home) for trials in progress, using 'mefloquine', 'Lariam', and 'malaria' as search terms. The search date was 22 June 2017.

SELECTION CRITERIA

We included randomized controlled trials (for efficacy and safety) and non-randomized cohort studies (for safety). We compared prophylactic mefloquine with placebo, no treatment, or an alternative recommended antimalarial agent. Our study populations included all adults and children, including pregnant women.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and risk of bias of trials, extracted and analysed data. We compared dichotomous outcomes using risk ratios (RR) with 95% confidence intervals (CI). Prespecified adverse outcomes are included in 'Summary of findings' tables, with the best available estimate of the absolute frequency of each outcome in short-term international travellers. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 20 RCTs (11,470 participants); 35 cohort studies (198,493 participants); and four large retrospective analyses of health records (800,652 participants). Nine RCTs explicitly excluded participants with a psychiatric history, and 25 cohort studies stated that the choice of antimalarial agent was based on medical history and personal preference. Most RCTs and cohort studies collected data on self-reported or clinician-assessed symptoms, rather than formal medical diagnoses. Mefloquine efficacyOf 12 trials comparing mefloquine and placebo, none were performed in short-term international travellers, and most populations had a degree of immunity to malaria. The percentage of people developing a malaria episode in the control arm varied from 1% to 82% (median 22%) and 0% to 13% in the mefloquine group (median 1%).In four RCTs that directly compared mefloquine, atovaquone-proguanil and doxycycline in non-immune, short-term international travellers, only one clinical case of malaria occurred (4 trials, 1822 participants). Mefloquine safety versus atovaquone-proguanil Participants receiving mefloquine were more likely to discontinue their medication due to adverse effects than atovaquone-proguanil users (RR 2.86, 95% CI 1.53 to 5.31; 3 RCTs, 1438 participants; high-certainty evidence). There were few serious adverse effects reported with mefloquine (15/2651 travellers) and none with atovaquone-proguanil (940 travellers).One RCT and six cohort studies reported on our prespecified adverse effects. In the RCT with short-term travellers, mefloquine users were more likely to report abnormal dreams (RR 2.04, 95% CI 1.37 to 3.04, moderate-certainty evidence), insomnia (RR 4.42, 95% CI 2.56 to 7.64, moderate-certainty evidence), anxiety (RR 6.12, 95% CI 1.82 to 20.66, moderate-certainty evidence), and depressed mood during travel (RR 5.78, 95% CI 1.71 to 19.61, moderate-certainty evidence). The cohort studies in longer-term travellers were consistent with this finding but most had larger effect sizes. Mefloquine users were also more likely to report nausea (high-certainty evidence) and dizziness (high-certainty evidence).Based on the available evidence, our best estimates of absolute effect sizes for mefloquine versus atovaquone-proguanil are 6% versus 2% for discontinuation of the drug, 13% versus 3% for insomnia, 14% versus 7% for abnormal dreams, 6% versus 1% for anxiety, and 6% versus 1% for depressed mood. Mefloquine safety versus doxycyclineNo difference was found in numbers of serious adverse effects with mefloquine and doxycycline (low-certainty evidence) or numbers of discontinuations due to adverse effects (RR 1.08, 95% CI 0.41 to 2.87; 4 RCTs, 763 participants; low-certainty evidence).Six cohort studies in longer-term occupational travellers reported our prespecified adverse effects; one RCT in military personnel and one cohort study in short-term travellers reported adverse events. Mefloquine users were more likely to report abnormal dreams (RR 10.49, 95% CI 3.79 to 29.10; 4 cohort studies, 2588 participants, very low-certainty evidence), insomnia (RR 4.14, 95% CI 1.19 to 14.44; 4 cohort studies, 3212 participants, very low-certainty evidence), anxiety (RR 18.04, 95% CI 9.32 to 34.93; 3 cohort studies, 2559 participants, very low-certainty evidence), and depressed mood (RR 11.43, 95% CI 5.21 to 25.07; 2 cohort studies, 2445 participants, very low-certainty evidence). The findings of the single cohort study reporting adverse events in short-term international travellers were consistent with this finding but the single RCT in military personnel did not demonstrate a difference between groups in frequencies of abnormal dreams or insomnia.Mefloquine users were less likely to report dyspepsia (RR 0.26, 95% CI 0.09 to 0.74; 5 cohort studies, 5104 participants, low certainty-evidence), photosensitivity (RR 0.08, 95% CI 0.05 to 0.11; 2 cohort studies, 1875 participants, very low-certainty evidence), vomiting (RR 0.18, 95% CI 0.12 to 0.27; 4 cohort studies, 5071 participants, very low-certainty evidence), and vaginal thrush (RR 0.10, 95% CI 0.06 to 0.16; 1 cohort study, 1761 participants, very low-certainty evidence).Based on the available evidence, our best estimates of absolute effect for mefloquine versus doxycyline were: 2% versus 2% for discontinuation, 12% versus 3% for insomnia, 31% versus 3% for abnormal dreams, 18% versus 1% for anxiety, 11% versus 1% for depressed mood, 4% versus 14% for dyspepsia, 2% versus 19% for photosensitivity, 1% versus 5% for vomiting, and 2% versus 16% for vaginal thrush.Additional analyses, including comparisons of mefloquine with chloroquine, added no new information. Subgroup analysis by study design, duration of travel, and military versus non-military participants, provided no conclusive findings.

AUTHORS' CONCLUSIONS

The absolute risk of malaria during short-term travel appears low with all three established antimalarial agents (mefloquine, doxycycline, and atovaquone-proguanil).The choice of antimalarial agent depends on how individual travellers assess the importance of specific adverse effects, pill burden, and cost. Some travellers will prefer mefloquine for its once-weekly regimen, but this should be balanced against the increased frequency of abnormal dreams, anxiety, insomnia, and depressed mood.

General Practitioners' Perception of Risk for Travelers Visiting Friends and Relatives

BACKGROUND

General practitioners (GPs) are an important source of pre-travel health advice for travelers; however, only a few studies have investigated primary healthcare provider-related barriers to the provision of pre-travel health advice, particularly to travelers visiting friends and relatives (VFR). We aimed to investigate Australian GPs' knowledge, attitudes, and practices with regard to VFR travelers.

METHODS

A postal survey was sent to randomly sampled GPs in Sydney, Australia, in 2012. The questionnaire investigated GPs' perception of risk and barriers to the provision of advice to VFR travelers.

RESULTS

Of 563 GPs, 431 (76.6%) spoke a language other than English (LOTE) with 361 (64.1%) consulting in a LOTE. Overall, 222 (39.4%) GPs considered VFR travelers to be at higher risk than holiday travelers, with GPs consulting in English only [adjusted odds ratio (aOR) 1.65, 95% confidence interval (CI) 1.11-2.44, p = 0.01] and GPs considering long-term migrants as VFR travelers (aOR 1.86 95% CI 1.07-3.23, p = 0.03) remaining significant on multivariate analysis.

CONCLUSIONS

Multilingual GPs are a valuable resource to reducing language and cultural barriers to healthcare. Targeted education of this subgroup of GPs may assist in promoting pre-travel health assessments for VFR travelers. Awareness of the need for opportunistic targeting of migrants for pre-travel consultation through routine identification of future travel is needed.

Summary of recommendations for the prevention of malaria by the Committee to Advise on Tropical Medicine and Travel (CATMAT)

BACKGROUND

On behalf of the Public Health Agency of Canada, the Committee to Advise on Tropical Medicine and Travel (CATMAT) developed the Canadian Recommendations for the Prevention and Treatment of Malaria Among International Travellers for Canadian health care providers who are preparing patients for travel to malaria-endemic areas and treating travellers who have returned ill.

OBJECTIVE

To provide guidelines on risk assessment and prevention of malaria.

METHODS

CATMAT reviewed all major sources of information on malaria prevention, as well as recent research and national and international epidemiological data, to tailor guidelines to the Canadian context. The evidence-based medicine recommendations were developed with associated rating scales for the strength and quality of the evidence.

RECOMMENDATIONS

Used together and correctly, personal protective measures (PPM) and chemoprophylaxis very effectively protect against malaria infection. PPM include protecting accommodation areas from mosquitoes, wearing appropriate clothing, using bed nets pre-treated with insecticide and applying topical insect repellant (containing 20%-30% DEET or 20% icaridin) to exposed skin. Selecting the most appropriate chemoprophylaxis involves assessment of the traveller's itinerary to establish his/her malaria risk profile as well as potential drug resistance issues. Antimalarials available on prescription in Canada include chloroquine (or hydroxychloroquine), atovaquone-proguanil, doxycycline, mefloquine and primaquine.

A cohort study of risk factors for malaria among healthcare workers in equatorial Guinea: stay away from the ground floor

BACKGROUND

Nonimmune long-term travelers to sub-Saharan Africa are at a high risk of contracting malaria. Most previous studies described risk factors and spatial distribution only in short-term travelers. This study describes the epidemiology and spatial distribution of malaria cases among expatriate healthcare workers in Equatorial Guinea.

METHODS

We conducted a cohort study evaluating the risk factors for malaria among healthcare personnel working in a hospital in Bata, Equatorial Guinea. Demographic data were recorded for all workers, and the spatial distribution of malaria cases within the hospital perimeters was determined.

RESULTS

During 2008 noncomplicated falciparum malaria was diagnosed in 13/102 workers (12.75%). On univariate analysis, the factors negatively associated with the risk of contracting malaria were living above the first floor and being older than 30 years. This association remained significant in multivariate analysis [hazard ratio (HR) = 0.24, 95% confidence interval [CI] = 0.06-0.91 for subjects living above the first floor and HR = 0.14, 95% CI = 0.04-0.52 for subjects above 30 years old]. Males and smokers had increased risk of contracting malaria on univariate analysis. However, this association was not significant in multivariate analysis (HR = 3.37, 95% CI = 0.87-13.1 and HR = 3.12, 95% CI = 0.83-11.75, for univariate and multivariate analysis, respectively). Low compliance with malaria prevention guidelines was observed in the study cohort.

CONCLUSIONS

Living on the ground floor of apartment buildings in sub-Saharan Africa, as opposed to living on the top floors, confers an increased risk of acquiring malaria in long-term travelers with low compliance to prophylaxis. These findings should be discussed in advance with people intending to stay in sub-Saharan Africa for an extended period of time. The association between belonging to a younger age group and an increased risk of acquiring malaria, and the marginally significant increased risk of malaria in males and smokers, can probably be explained by increased exposure to malaria vectors. The compliance of healthcare workers with malaria prophylaxis is extremely low, as was previously described for other long-term residents.

Travel health knowledge, attitudes and practices among Australasian travelers

BACKGROUND

Although the Asia Pacific region is the focus of the fastest-growing tourist and travel industry, few data are available on the knowledge, attitudes and practices (KAP) of travelers from this region with regard to travel-related infectious diseases.

METHODS

We conducted a cross-sectional survey among travelers at the departure lounges of five airports in Australasia (Singapore, Kuala Lumpur, Taipeh, Melbourne, Seoul) whose travel destinations were Asia, Africa or South America. Two standardized questionnaires directed towards KAP in travel health, travel immunizations and malaria were administered.

RESULTS

Of 2,101 respondents (82% Asian, 17% Western), 31% had sought pretravel health advice and only 4% sought travel health advice from the travel medicine specialist. The risk of vaccine-preventable infectious diseases and malaria at the destination country was perceived to be low. Overall, fewer than 5% of travelers had been vaccinated in preparation for their trip. The most frequent travel vaccinations were for hepatitis A and B. Only 40% of travelers to malaria-endemic areas carried malaria prophylaxis. Compared to Western travelers, those of Asian nationality were significantly less likely to obtain pretravel advice and malaria prophylaxis and to receive travel vaccinations.

CONCLUSION

There is an urgent need for increased awareness about travel-related infectious diseases among Asian travelers, and greater uptake of pretravel health advice, vaccinations and malaria prophylactic measures.

Preparing the traveller

The four steps for giving travellers the foundation for healthy journeys are to assess their health, analyse their itineraries, select vaccines, and provide education about prevention and self-treatment of travel-related diseases. This process takes time. Since there is a risk of information overload, travellers should leave the clinic with some written advice for reinforcement. The order of these steps can be tailored to what best suits the travel clinic, but vaccinating early in the process allows monitoring for adverse reactions. Face-to-face discussion is vital for explaining the use and side-effects of medications. Those who provide a travel medicine service should be seeing many travellers and should seek specialist training. In 2003, the International Society of Travel Medicine introduced a certificate of knowledge examination in travel medicine. We cannot make travellers bullet-proof but it is possible to make them bullet-resistant. The pre-travel visit should minimise health risks specific to the journey, give travellers the capability to handle most minor medical problems, and allow them to identify when to seek local care during the trip or on return.

Problems in prescribing malaria chemoprophylaxis for travelers

To offer effective malaria chemoprophylaxis for travelers in a country, the physician must know the precise status of malaria there (frequency, resistance), determine the degree of exposure to mosquito bites, evaluate the precise clinical condition of the traveler, and improve the traveler's compliance with treatment by providing good information on potential side-effects. These side-effects, sometimes overemphasized in the media, lead to poor compliance, particularly after returning home, and, consequently, increase the risk of acquiring malaria. The recently approved Malarone could overcome these drawbacks. But its cost is high and its wide use could also lead to the emergence of resistant strains. Therefore, training professionals in travel medicine is important in malaria prevention and decrease the prescription of abusive or inaccurate prophylaxis (e.g., most tourists traveling in organized tours in Asia, with no stay in remote malaria endemic areas, do not need any prophylaxis). In addition, prevention of mosquito bites with repellents, impregnated bed nets, and indoor insecticide-dispensing devices is still an important tool for controlling malaria in travelers.

Chemoprophylaxis use and the risk of malaria in travelers to Nepal

BACKGROUND

Malaria transmission in Nepal is focal and seasonal. Based on data in returning travelers the risk of malaria is low. Sources of advice give contradictory information regarding the need for chemoprophylaxis. As a result, a degree of confusion exists among visitors. The aim of this study was to describe chemoprophylactic practices among travelers to Nepal and to document differences in advice according to its source and the country in which it was given.

METHODS

A questionnaire survey of tourists attending the CIWEC Clinic Travel Medicine Center, Kathmandu between June 2000 and May 2001. Resident expatriates and indigenous Nepalese were excluded.

RESULTS

Completed questionnaires were obtained from 1,303 respondents. Two hundred and eighty-eight respondents were taking chemoprophylaxis specifically for their trip to Nepal (22%), whereas 958 were not. Travelers from the United Kingdom and Denmark were significantly more likely, and those from the United States and Germany significantly less likely, to be taking chemoprophylaxis. Most travelers sought pretravel advice (71%), and all sources were more likely to advise them not to take chemoprophylaxis than to take it. However, travelers advised by a family practitioner were significantly more likely to be taking chemoprophylaxis than those advised by a travel medicine specialist. Of those taking chemoprophylaxis, 53% were doing so for a visit to the Terai alone, 33% for all areas of Nepal, and 6% for the Kathmandu Valley. Nine different chemoprophylactic regimes were in use. Six hundred and forty respondents who were not taking chemoprophylaxis had been advised that it was not necessary; 276 had made the choice themselves; and 131 had been taking chemoprophylaxis but had stopped while in Nepal. Twenty-eight of these respondents had stopped because of side effects. The most common reason for choosing not to take chemoprophylaxis was either the occurrence of side effects or the fear of them (31%).

CONCLUSIONS

The variable and ultimately low risk of contracting malaria in Nepal has resulted in a lack of consensus and a wide range of opinion regarding the need for chemoprophylaxis. There is a need for clarification and tighter definition of the malaria risk faced by travelers to Nepal to avoid unnecessary chemoprophylaxis use while protecting those at significant risk.

Pre-travel advice: an overview

The message of the pre-travel provider is necessarily paradoxic. First the provider lists a score of causes of illness and premature demise, and then states, "But it sounds like a great trip and I think you'll have fun." Pre-travel providers need to walk a fine line: they must encourage patients to be cautious but not paranoid, optimistic but realistic. This discussion is complicated further by the fact that risk reduction is not the only consideration; if it were, practitioners would advise patients to remain in the developed world and foray from their homes only to visit health clubs and the fruit-and-vegetable section of grocery stores. A tacit assumption in travel medicine is that some degree of acceptance of heightened risk is tolerated for the benefit of improved quality of life offered by travel abroad. The amount of risk that is reasonable to accept for a given benefit in quality of life yielded by travel cannot be quantified, however. Providers must render judgments on what is "reasonable" and what is not, and this complex decision is based on equal parts medical knowledge and intuition. At one extreme, mountaineers in Nepal have been found to have a 2.4% mortality rate per expedition [83,84]. The travel provider might make the reasonable decision to counsel these travelers to avoid that activity. These travelers most likely will ignore that advice, at which point the provider must endeavor to reduce risk to the extent possible. Other situations in which the provider should advise a change in itinerary or activities include counseling parents who plan to take an infant to high altitude or a pregnant woman who plans to scuba dive. If travelers remain cloistered in their hotel rooms, eating all meals from room service and watching CNN, then it could be suggested that they are overly risk-adverse and might consider foraying out of the hotel, despite the potential associated increased risks to health. Conversely, if travelers find themselves on motorcycles after a few drinks with a new love interest, they are perhaps not sufficiently risk-adverse; however, the "point of optimal risk acceptance" between these two extremes is a matter of conjecture. Risks associated with travel can never be eliminated; however, appropriate advice and immunizations can tilt the odds in travelers' favor.