Nicaragua doesn't require any vaccinations for entry, but standard travel vaccinations are recommended: hepatitis A, typhoid, and a tetanus booster are the basics. Hepatitis B is worth considering for longer stays. Visit a travel clinic at least a month before departure.
Mosquito-borne illness is the main health concern. Dengue fever is present throughout the country — there's no vaccine, so prevention is key. Use a repellent with at least 20% DEET, wear long sleeves and trousers at dawn and dusk, and sleep under a mosquito net or in screened accommodation. Zika and chikungunya are also present; pregnant travelers should consult their doctor before visiting.
Malaria risk exists but is concentrated in the Caribbean lowlands (the RAAN and RAAS autonomous regions). Travelers sticking to Pacific-side destinations and Managua face minimal malaria risk. If you're heading to the Caribbean coast or spending time in rural eastern Nicaragua, consult a travel clinic about prophylaxis.
Water from the tap is not safe to drink in most of the country. Bottled water is cheap and widely available. In Granada and Managua, some upscale hotels have filtered water, but the default should be to buy bottled or use a filter. Avoid ice in local restaurants outside tourist areas.
Stomach bugs are common among travelers, usually from food or water. Most resolve in a day or two; oral rehydration salts are useful to carry. Be cautious with street food that's been sitting around — freshly cooked is generally fine.
Medical care in Managua is reasonable; the Hospital Vivian Pellas is the best private hospital and is used by most expats and travelers with serious issues. Outside the capital, facilities are basic. Travel insurance with medical evacuation coverage is strongly recommended.
Pharmacies (farmacias) are plentiful and generally well-stocked. Many common medications can be bought over the counter in Nicaragua that require a prescription at home. Prices are low.