By Reuters Staff

(Reuters Health) – Many common travel vaccines don’t have known safety risks for pregnant women, although a research review also suggests that evidence is limited for some inoculations.

Researchers examined data from trials of common travel vaccines and found high quality evidence that two – the flu vaccine and the Tdap vaccine (against tetanus, diphtheria and pertussis) – are safe for pregnant women and their babies.

Beyond these two vaccines, researchers found moderate or low quality evidence that there are no safety issues with several other common travel vaccines: meningococcus; yellow fever; rubella; hepatitis A; hepatitis B; rabies; and polio.

“Overwhelming evidence supports the safety of influenza and Tdap vaccines during pregnancy,” lead study author Dr. Roni Nasser of Rambam Health Care Campus in Haifa, Israel, and colleagues write.

“It is likely that other vaccines, including the live attenuated yellow fever, meningococcal, hepatitis A, hepatitis B, and rabies vaccines are also safe,” Nasser and colleagues write. “For other vaccines, such as MMR (measles, mumps, rubella), typhoid, polio, Japanese encephalitis, and tick- borne encephalitis vaccines, no safety data during pregnancy are available.”

The flu and Tdap vaccines are both routinely recommended for pregnant women, whether or not they travel, according to the U.S. Centers for Disease Control and Prevention.

For many other routine vaccinations, women are advised to weigh the potential benefits and harms of vaccinations and make a decision with their doctors on a case-by-case basis, according to the CDC.

While women are also advised to weigh the risks and benefits of pre-travel vaccines on a case-by-case basis, they may also want to consider whether travel can be postponed to avoid the need for vaccination as well as any potential side effects from vaccines, the study authors note in the Journal of Travel Medicine.

“Although our analyses of the existing data generally points to no harm associated with vaccines, it is important to note that most trips can be canceled or delayed,” the authors advise.

“As such, during outbreaks of yellow fever, for example, travel of pregnant women should be discouraged,” the study team writes. “Conversely, when exposure to a deadly infection such as yellow fever is prolonged and unavoidable, vaccines should be used.”

In public health emergencies, when exposure to diseases with devastating consequences for pregnant women and their babies is unavoidable, vaccines may be used even if the safety isn’t clear for pregnant women, the researchers note.

The World Health Organization, for example, advised use of a new Ebola vaccine in pregnant women during recent outbreaks even though there isn’t any safety data available related to pregnancy, the study authors point out.

Women generally can travel up until the last few weeks of pregnancy, although women with certain complications like dangerously high blood pressure or who are pregnant with multiples may be advised to avoid travel.

The CDC currently recommends that pregnant women avoid travel to areas with outbreaks of Zika, a mosquito-borne illness that can cause serious birth defects, or where malaria, another mosquito-borne illness that can harm babies, is common.

SOURCE: Journal of Travel Medicine, online October 16, 2019.