BACKGROUND AND PURPOSE:

• The safety of travel vaccines for pregnant women is relatively unknown
• Nasser et al. (Journal of Travel Medicine, 2019) studied the safety profiles of vaccines commonly given to travelers in pregnant women

METHODS:

• Systematic review and meta-analysis
• Study inclusion criteria
  • Case series | Cohort studies | RCTs
  • Only RCTs comparing vaccine to placebo or to no vaccine were included
• Data analysis
  • Risk ratios (RR) and 95% CIs were calculated as the summary measure
• Primary outcomes
  • Severe systemic adverse events
  • Maternal outcomes related to the course of pregnancy
  • Neonatal outcomes
  • Local adverse events

RESULTS:

• Influenza vaccine
  • The safety of influenza vaccine was supported by high-quality evidence
• Tdap vaccine
  • No evidence of any harm was found in the meta-analysis of RCTs
  • There was a slight increase in chorioamnionitis rate reported in 3 of 12 observational studies
• Meningococcal vaccine
  • Determined as probably safe during pregnancy, as supported by RCTs comparing meningococcal vaccines to other vaccines
  • No RCTs comparing meningococcal vaccine with placebo or no vaccine
• Hepatitis A and B vaccine
  • Data from observational studies support the safety of hepatitis A, hepatitis B
• Rabies vaccine
  • Data from observational studies support the safety of rabies vaccine
• Live attenuated yellow fever vaccine
  • Data from observational studies support the safety of the yellow fever vaccine
• Little to no data were found about the safety of the following
  • Polio
  • Typhoid
  • Japanese encephalitis
  • Tick-borne encephalitis
  • MMR

CONCLUSION:

• RCTs comparing vaccine to placebo or no vaccine support the safety of the influenza and Tdap vaccine in pregnancy
• Meningococcal vaccine
  • Considered safe during pregnancy (moderate level of evidence)
  • Pregnant travelers are likely to be at very low risk of infection unless travelling to
    • Areas with outbreaks | Mass gatherings | Prolonged stay in low-income setting | Specific high risk geographic areas (e.g., African ‘meningococcal belt’)
• Yellow fever vaccine
  • Associated with high mortality rates
  • Likely there is either no risk or risks very low (low-quality evidence)
  • WHO and CDC recommend that if a pregnant woman must travel to a country with a current high-transmission risk and exposure is prolonged, the benefits of vaccination would outweigh any theoretical risks
• Rabies vaccine
  • Universally fatal and animal bites are possible during travel
  • Data on vaccine safety in pregnancy is scarce
  • “Probably safe to administer” (low-quality evidence)
  • Recommended that “the use of rabies vaccines be considered only for pregnant travellers who are unlikely to have access to post-exposure prophylaxis that includes both rabies vaccination and rabies immunoglobulin”
  • No limitations for post-exposure prophylaxis in pregnancy
• Hepatitis A vaccine
  • Risk high in low-income countries
  • Hepatitis A in pregnancy has been associated with adverse outcomes such as preterm labor
  • Data on vaccine safety in pregnancy is scarce but “likely to be safe” (low-quality evidence)
  • If travel to country with high-transmission risk is unavoidable during pregnancy, vaccination “should be considered”
• Hepatitis B vaccine
  • Since transmission is via sexual contact, contaminated needles, tattoos or contaminated blood products, risk of transmission during travel is unlikely for most travelers
  • Series of shots will likely not be practical for many pregnant women
  • Consider vaccine “only if known risk factor for hepatitis B is present” (low level evidence)
• No evidence of harm for the polio, typhoid, Japanese encephalitis, tick-borne encephalitis and MMR vaccines, though data were limited

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Learn More – Primary Sources:

Are all vaccines safe for the pregnant traveler? A systematic review and metaanalysis

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