This summer I will spend a month teaching nurses in Tanzania. In preparation for my trip, I'm reviewing travel medicine recommendations and would like to address some developments since my previous post on travel immunizations.
In previous years, the Centers for Disease Control and Prevention (CDC) reported that most of the cases of measles in the United States are associated with importations from countries where measles immunization coverage is low. In the first 5 months this year, there have been more cases of measles in this country than in any year since 2000 when measles was eliminated from the U.S.
Once again, most of those cases are associated with importations, nearly half of which were travelers returning from the Philippines, and most of the cases are unvaccinated people. There has also been a large outbreak of measles in Fraser Valley, B.C. that centered on a community with low measles immunization coverage and was associated with importation from the Netherlands. Here in Washington State there were several cases associated with the Fraser Valley outbreak in Whatcom County. One individual traveled to King and Pierce Counties. Fortunately, there were no known cases from those exposures.
The CDC reiterated its measles vaccine recommendation for travelers.
On May 5th 2014 the Director General of the World Health Organization (WHO) declared ongoing international transmission of wild polio virus (WPV) a public health emergency and issued temporary requirements for polio immunization for travel between countries that are currently exporting WPV.
WHO requested the following countries ensure that long-term visitors (more than 4 weeks) show documentation of a polio vaccine booster between 4 weeks and 12 months prior to departure (countries currently exporting WPV):
WHO requested the following countries encourage long-term visitors (more than 4 weeks) to receive a polio vaccine booster between 4 weeks and 12 months prior to departure (countries with active WPV transmission but not currently exporting WPV):
· Equatorial Guinea
These are measures are temporary and may change.
The CDC maintains its recommendation the travelers to polio-affected countries are fully vaccinated against polio and that adults receive a one-time polio vaccine booster.
As I discussed in my previous post, International Health Regulations (IHR) require yellow fever vaccanation for travel between certain countries. The requirement includes booster doses of yellow fever vaccine every 10 years.
Last year the WHO Strategic Advisory Group of Experts (SAGE) on immunizations examined the effectiveness and duration of immunity of yellow fever vaccine and concluded that, for healthy people, immunity to yellow fever from a single dose of vaccine is probably life-long and that booster doses are not required. Further research is needed to determine in the efficacy and safety of yellow fever vaccine in certain populations including people who are immunocompromised and pregnant woman.
The current recommendations for booster doses of yellow fever vaccine every 10 years will remain in effect until June 2016 – long before I'm due for another dose.
There are specific recommendations for each of the vaccines that I've discussed. For example, documentation of receipt of a yellow fever vaccine may only be required for persons traveling from an endemic country and may not be required for a person traveling directly from the United States. International Health Regulations require that yellow fever vaccine be administered at an authorized yellow vaccine clinic.
There are also specific contraindications and precautions for each of these vaccines.
In addition to required and recommended vaccines, there are other recommendations for travelers for health risks specific to endemic counties or areas within those countries.
|I'll miss you while I'm away, little man.|
Centers for Disease Control and Prevention. (2000). Poliomyelitis prevention in the United States. Updated recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report, 49(5), 1-22. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr4905a1.htm.
Centers for Disease Control and Prevention. (2009). Updated recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding routine poliovirus vaccination. Morbidity and Mortality Weekly Report, 58(30), 829-830. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5830a3.htm.
Centers for Disease Control and Prevention. (2013). Clinical update: yellow fever vaccine booster. http://wwwnc.cdc.gov/travel/news-announcements/yellow-fever-vaccine-booster.
Centers for Disease Control and Prevention. (2014). Guidance to U.S. clinicians regarding new WHO polio vaccination requirements for travel by residents of and long-term visitors to countries with active polio transmission. http://emergency.cdc.gov/han/han00362.asp.
Gastañaduy, P. A., Redd, S. B., Fiebelkorn, A. P., Rota, J. S., Rota, P. A., Bellini, W. J. et al. (2014). Measles – United States, January 1 – May 23, 2014. Morbidity and Mortality Weekly Report, 63(22), 496-499. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6322a4.htm.
Gotuzzo, E., Yactayo, S., & Córdova, E. (2013). Efficacy and duration of immunity after yellow fever vaccination: systematic review on the need for a booster every 10 years. American Journal of Tropical Medicine and Hygiene, 89(3), 434-444. http://www.ajtmh.org/content/89/3/434.long.
McLean, H. Q., Fiekelkorn, A. P., Temte, J. L., & Wallace, G. S. (2013). Prevention of measles, rubella, congenital rubella syndrome, and umps, 2013. Summary recommendations of the Advisory Committee on Immunization Practices. Morbidity and Mortality Weekly Report, 62(4), 1-34. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr6204a1.htm.
Staples, J. E., Gershman, M., & Fischer, M. (2010). Yellow fever vaccine. Recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report, 59(7), 1-27. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5907a1.htm.
World Health Organization. (2013). Meeting of the Strategic Advisory Group of Experts in immunizations, April 2013 – conclusions and recommendations. Weekly Epidemiological Review, 88(20), 201-216. http://www.who.int/wer/2013/wer8820.pdf.
World Health Organization. (2013). Vaccines and vaccination against yellow fever. Weekly Epidemiological Review, 88(27), 269-283. http://www.who.int/wer/2013/wer8827.pdf.
World Health Organization. (2014). WHO guidance for implementation of the IHR temporary recommendations under the IHR (2005) to reduce the international spread of polio. http://www.polioeradication.org/Portals/0/Document/Emergency/PolioPHEICguidance.pdf.
World Health Organization. (2014). Yellow fever vaccination booster. http://www.who.int/ith/updates/20140605/en.