How far in advance to get travel vaccinations?
I will be traveling to Costa Rica and Chile over the next 6-12 months and spending 1-2 months in each country while I am there.
I checked the CDC website for Costa Rica and Chile, as well as the general vaccination guidelines page, and it recommends that I get vaccinated for Hepatitis A and B and Typhoid 3-4 weeks before I travel.
Is it necessary to wait, or can I get these vaccinations done now so that I have one more thing out of the way? Are travel vaccinations like "routine" vaccinations in that you just need to keep up on them every year or so, or do you really need to take them closer to when you travel?
The advice to get vaccinated 3-4 weeks prior to traveling should be read as "at least 3-4 weeks prior". Typically, it takes your body's immune system a little while to respond to the vaccine by creating antibodies. Thus, if you travel immediately after getting a vaccination, you may still be vulnerable to those infections.
In the case of hepatitis vaccine the protection it affords will last 10 years. So getting it a bit sooner than 4 weeks prior to travel is a non-issue. I've never heard of a traveler-oriented vaccine that doesn't afford at least 3 years protection.
So, in summary, if it is more convenient to get your vaccinations 6 months prior to travel, then go right ahead. Just keep track of the duration of their effectiveness for future travels. You'll need to 'top them up' sooner then otherwise as a consequence.
Also, more time between vaccination and travel gives you better options on vaccine schedules. Many are best spread out across multiple doses, with usually several weeks between doses, and if rushed in fewer or faster doses have increased risks of side effects or reduced effectiveness.