Altitude is the headline risk
Acute mountain sickness affects nearly half of travelers during their first 48 hours in Cusco — usually mild (headache, nausea, poor sleep), occasionally trip-wrecking. CDC guidance supports acetazolamide prophylaxis for fly-in itineraries like this one, alongside the non-drug move that helps most: descending to a lower valley (the Sacred Valley sits below Cusco) to sleep the first night or two. The standard adult regimen is 125 mg twice daily, started the day before ascent.
What the highlands do NOT require: malaria pills
There is no malaria transmission in Cusco, Machu Picchu, or Lake Titicaca — CDC lists these highland tourist areas as transmission-free. Malaria risk in Peru lives east of the Andes, below 2,500 m: the Amazon lowlands, including Iquitos and Puerto Maldonado. If your itinerary adds an Amazon extension, prophylaxis enters the picture — that’s exactly the kind of route-specific call your reviewing physician makes.
Stomach trouble is the quiet odds-on favorite
Peru sits in CDC’s high-risk tier for travelers’ diarrhea — attack rates run 30–70% over a two-week trip in high-risk regions. Most cases are mild and need fluids only; the standby antibiotic (azithromycin, carried and taken only if moderate-to-severe illness hits) exists for the case that would otherwise end the trek.
What needs a clinic, honestly
Yellow fever vaccine is not required for Peru entry and not recommended for Cusco, the Inca Trail, Machu Picchu, or Lima — but it IS recommended if your route dips into the eastern lowlands (Madre de Dios, Loreto, Ucayali). That’s an injection at a certified yellow fever center, which no pill consult can provide — ours included. Typhoid vaccination is recommended for most travelers to Peru; the injectable version is a clinic visit too.
What a $49 consult typically covers here
- Acetazolamide — altitude illness prophylaxis
- Azithromycin — travelers’ diarrhea standby (self-treatment)
For a highlands-only itinerary, a typical plan centers on altitude prophylaxis + standby diarrhea treatment. Add the Amazon and the malaria conversation opens. Your physician composes the final plan for your exact route. Sources: CDC destination pages + Yellow Book 2026.