The pregnant traveler

Are all vaccines safe for the pregnant traveller? A systematic review and meta-analysis

Pregnant travellers and their offspring are vulnerable to severe outcomes following a wide range of infections. Vaccine-preventable diseases can have a particularly severe course in pregnant women, but little is known about the safety of travel vaccines in pregnant women. We performed a systematic review of all published literature concerning the safety of vaccines frequently given to travellers such as yellow fever, MMR (mumps, measles and rubella), influenza, Tdap (tetanus, diphtheria and pertussis), meningococcus, hepatitis A and B, rabies, polio, typhoid fever, tick-borne encephalitis and Japanese encephalitis vaccines. We included case series, cohort studies and randomized controlled trials (RCTs). For the meta-analysis, we included only RCTs that compared the administration of a vaccine to placebo or to no vaccine. Outcome measures included severe systemic adverse events, maternal outcomes related to the course of pregnancy, neonatal outcomes and local adverse events. We calculated the risk ratio and its 95% confidence interval as the summary measure. The safety of influenza vaccine is supported by high-quality evidence. For Tdap vaccine, no evidence of any harm was found in the meta-analysis of RCTs. A slight increase in chorioamnionitis rate was reported in 3 out of 12 observational studies. However, this small possible risk is far outweighed by a much larger benefit in terms of infant morbidity and mortality. Meningococcal vaccines are probably safe during pregnancy, as supported by RCTs comparing meningococcal vaccines to other vaccines. Data from observational studies support the safety of hepatitis A, hepatitis B and rabies vaccines, as well as that of the live attenuated yellow fever vaccine. We found little or no data about the safety of polio, typhoid, Japanese encephalitis, tick-borne encephalitis and MMR vaccines during pregnancy.

Pregnancy course and outcome in women traveling to developing countries

BACKGROUND

The issue of travel to developing countries during pregnancy has not been sufficiently studied. The aim of this study is to investigate the rate, course, and outcome of pregnancies in women who traveled to developing countries while pregnant, or became pregnant during such travel.

METHODS

Women visiting two major travel clinics in Israel for consultation within the years 2004 to 2009, who were pregnant or declared an intention of becoming pregnant during travel were contacted. This was followed by a telephone interview by an obstetrician with those women who were actually pregnant. Background characteristics, morbidity during travel, and pregnancy course and outcome were collected.

RESULTS

Overall 52,430 travelers' records had been screened. Of these, we identified 49 women who were pregnant during their trip, but 3 declined participation. Of the remaining 46 women, 33 were pregnant at departure, and 13 conceived during travel. The incidence of pregnancy during travel was thus 0.93/1000 travelers. Thirty-three women traveled to East Asia, 8 to South and Central America, 5 to Africa. More than two thirds of women received pretravel vaccinations. Adherence to the World Health Organization recommendations regarding food and drink was high (87%) and travelers' diarrhea occurred in only 11% of women. Five of 22 women traveling to malarious areas had taken antimalarial prophylaxis. Six women required medical therapy during travel. Pregnancy outcome was not different from the normal population except for an unusually low rate of preterm delivery.

CONCLUSIONS

In this cohort, travel to developing countries was not associated with adverse pregnancy outcome. Larger studies are needed to support these findings.

The pregnant traveler

The care of the pregnant traveler is both challenging and rewarding. It requires clinical information and skills that are derived from many disciplines. This article reviews preparatory guidelines for safe travel by the pregnant mother and her most important travel companion, the developing fetus. Issues considered are pretravel risk assessment, immunizations, and prevention of travelers' diarrhea and hepatitis. The safety and efficacy of malaria chemoprophylaxis in the present context of widespread multidrug-resistant malaria is discussed, and guidelines are offered for both prevention and treatment. A safety profile of commonly used travel medications, antibiotics, and antiparasitic drugs is reviewed.

Infectious diseases

Routine antenatal screening can detect some potentially serious infectious diseases or susceptibility to infection and allow intervention to prevent adverse outcomes. However, screening programmes can only be justified if appropriate criteria are met for the quality of laboratory tests and interventions. For many infections that are associated with adverse maternal or fetal effects, there are no suitable, cost-effective methods of screening or prevention. However, early diagnosis of infection in high-risk women or those with symptoms can allow preventive intervention. Acute febrile illness or other symptoms consistent with infection during pregnancy should be investigated more diligently than in a non-pregnant woman. Early diagnosis of an apparently trivial maternal infection may prevent serious fetal disease. When the diagnosis of maternal infection is made, appropriate action depends on the nature of infection and the stage of pregnancy at which it occurs. The results of serological test should be confirmed, preferably by a reference laboratory, by retesting the original specimen(s) and/or testing further specimens, as appropriate. Management decisions generally should be made in consultation with an infectious disease physician or clinical microbiologist with experience of infectious diseases in pregnancy.