Compliance with Primary Malaria Chemoprophylaxis: Is Weekly Prophylaxis Better Than Daily Prophylaxis?

Travellers' adherence to atovaquone/proguanil malaria chemoprophylaxis after return from endemic areas

BACKGROUND

According to current guidelines, atovaquone/proguanil (AP) malaria chemoprophylaxis is taken once daily during travel, and continued for seven days after return from malaria-endemic areas. However, pharmacokinetic data and studies on drug-sparing AP regimens suggest that AP could possibly be discontinued upon return without loss of protection. Besides being more cost-effective, shorter AP regimens may enhance adherence. We aimed to investigate adherence to the current AP chemoprophylaxis regimen during the seven days post-travel, and travellers' preferences for potential drug-sparing AP regimens.

METHODS

In this cross-sectional study, adult travellers, who were prescribed AP chemoprophylaxis during a pre-travel consultation between 01-12-2022 and 01-12-2023 at the Amsterdam UMC travel clinic, were send a post-travel online questionnaire. The primary outcome was the proportion of travellers non-adherent to AP during the seven days post-travel, defined as missing one tablet or more. Secondary outcomes were non-adherence during travel, reasons for non-adherence, and AP regimen preferences.

RESULTS

The questionnaire was completed by 62 % (382/614) of contacted travellers. Of the participants, 31 % (117/382) reported non-adherence during the seven days post-travel; during stay this was 16 % (58/382). Frequently reported reasons for non-adherence were: forgetfulness, low self-perceived malaria risk, and adverse effects. An alternative AP regimen discontinuing AP upon return was deemed most appealing and easy to adhere by 73 % (276/376) of participants.

CONCLUSIONS

Non-adherence was high during the seven days after return. Travellers preferred an alternative AP chemoprophylaxis regimen, allowing them to discontinue upon return. Future research shall be conducted to investigate whether AP could be discontinued upon return.

Antimalarial prophylaxis failure: Malaria in a returning traveler despite mefloquine prophylaxis

This case report presents a perplexing case of Plasmodium malariae breakthrough infection despite prophylaxis with appropriate antimalarial prophylactic regimen of mefloquine in a compliant patient. A 78-year-old missionary who travels each year to the African subcontinent for multiple weeks to months, over 25 years, adheres to stringent antimalarial prophylaxis with Mefloquine as prescribed, starting prior to the trip and continuing after the return to the U.S.A. She gave no prior history of malaria during her 25 years of travel to Africa and back. Since she had no prior history of malaria and due to her excellent compliance with antimalarial regiment, despite her presentation which were suggestive of malaria, neither the patient nor her providers recognized the onset of malaria in this case. Infectious diseases physicians approached this case with an open mind, investigated appropriately, requested appropriate tests, found the presence of malarial parasite, identified as P. malariae species thereafter. She was started on antimalarial treatment in a timely fashion and showed an excellent response. This intriguing recovery of malarial parasite and response to treatment despite the patient being on antimalarial prophylaxis raised the possibility of mefloquine failure as an antimalarial prophylactic agent against P. malariae species.

Questionnaire-Based Analysis of Adverse Events and Compliance with Malaria Chemoprophylaxis in Taiwan

Malaria was eradicated in Taiwan in 1952; however, imported malaria cases are reported every year. The subtropical climate in Taiwan permits mosquito propagation and possible outbreaks of mosquito-borne diseases. The aim of this study was to investigate travelers' compliance and side effects of malaria prophylaxis to prevent a malaria outbreak in Taiwan. In this prospective study, we enrolled travelers who visited our travel clinic before going to malarious areas. A total of 161 questionnaires were collected and analyzed. Associations between the occurrence of side effects and compliance with antimalarial drugs were analyzed. Adjusted odds ratios were calculated after adjusting for potential risk factors in multiple logistic regression analysis. Of the 161 enrolled travelers, 58 (36.0%) reported side effects. Insomnia, somnolence, irritability, nausea, and anorexia were associated with poor compliance. Mefloquine was not associated with more neuropsychological side effects than doxycycline. Multiple logistic regression analysis showed that chemoprophylaxis compliance was affected by a younger age, visiting friends and relatives, visiting the travel clinic more than 1 week before the trip, and preferring to use the same antimalarial regimen on the next trip. Our findings could provide information to travelers besides labeled side effects to improve compliance with malaria prophylaxis and consequently help to prevent malaria outbreaks in Taiwan.