⅕ Dose of Stamaril Yellow Fever Vaccine Protects for 10 Years

A new study reported that a one-fifth fractional dose of the Stamaril (17D-YFV) yellow fever vaccine delivers protective antibodies for up to 10 years. 

This research supports previous evidence that deploying ‘fractional dosing’ is an adequate vaccination strategy when vaccine supply is constrained. 

One reason yellow fever vaccines can become scarce during outbreaks is that it takes 12 months to produce additional vaccines. 

This is good news since fractional dosing has been used in recent years during yellow fever virus outbreaks in Brazil and the Democratic Republic. 

Previous studies showed that a reduced dose of Sanofi’s Stamaril (17D-YFV) vaccine extended protection for up to a year, but questions remained about a smaller dose's long-term strength. 

These researchers studied 40 adults who were given a one-fifth fractional dose 10 years ago and found that 39 of them still had protective antibodies in their systems. 

This randomized, controlled clinical trial was conducted from 2005 to 2007 at Leiden University Medical Center. It included 75 participants who received either a 0.1-milliliter (mL) fractional vaccine dose intradermally or the standard 0.5-mL dose subcutaneously. 

Participants who received a booster dose during the 10-year follow-up were excluded from the study. Both study groups received the same vaccine, manufactured by Sanofi Pasteur. 

The majority of people infected with the yellow fever virus will either not have symptoms or have mild symptoms and completely recover, says the CDC.   

Because there is a risk of severe disease, all people who develop yellow fever symptoms after traveling to or living in an area at risk for the virus should see their healthcare provider. 

Once you have been infected, you are likely to be protected from future infections. 

The World Health Organization (WHO) recently published updates to the country-based yellow fever recommendations and certificate requirements. 

Proof of vaccination is often required for travelers arriving from countries with a risk of yellow fever transmission and sometimes travelers in transit through such countries. 

For American citizens traveling abroad, the US Centers for Disease Control and Prevention (CDC) Travel website publishes information about which countries require yellow fever vaccination for entry and how countries the CDC recommends yellow fever vaccination. 

To prevent getting sick from the yellow fever virus, the CDC recommends using insect repellent, wearing long-sleeved shirts and long pants, and getting vaccinated. 

International travelers can find convenient locations to schedule a vaccination appointment by visiting Vax-Before-Travel.

The CDC Vaccine Price List provides private sector vaccine prices for general information. And vaccine discounts can be found on this webpage.   

Vaccines, like any medicine, can have side effects. You are encouraged to report negative side effects of vaccines to the CDC.