Large numbers of travelers are visiting developing countries, like India. Studies show that 50-75% of travelers to the tropics and sub-tropics (including India) report some health problem during their stay or after leaving the country which they visited although most of the health problems are minor and only about 5% require medical attention and less than 1% requires hospitalization (1). Infectious diseases are the main culprit for the health problems among the travelers. But they rarely cause death among travelers.
It is your personal doctor (or immunologist, or infectologist) who will tell you which vaccinations you need before travel, and if vaccination is safe for you. If you travel to India, you should set up an appointment to your doctor 4-6 weeks before traveling, since in this time most of vaccines take effect (2).
Immunizations (vaccination) for travelers can be categorized into three categories:
a) Routine Vaccinations
Routine vaccinations such as for influenza, chickenpox, polio, measles/mumps/rubella (MMR), and diphtheria/pertussis/tetanus (DPT), also for rotavirus, are for children and for adult booster doses of vaccines and these are regardless to travel requirements (2).
b) Required Vaccinations
Yellow Fever Vaccination
Yellow fever is caused by yellow fever virus and transmitted to humans through the bite of infected mosquitoes. Symptoms in a mild infection last for 3-4 days and include fever, muscle aches, headache, nausea and vomiting. In some patients, after few days of recovery, a toxic phase with bleeding from the nose, mouth and eyes, heart problems, jaundice, decreased urination, and shock with affected consciousness may follow and may be fatal. No treatment for yellow fever is currently available.
An entry into India requires vaccination for yellow fever for travelers from certain countries where yellow fever is endemic (some African, South American and Caribbean countries). Travelers from Europe, North America, Australia, and continental Asia do not need to be vaccinated against yellow fever to be able to enter India. Yellow fever vaccine is for the country (in this case India) so that yellow fever is not introduced in India (yellow fever is absent in India).
Yellow fever vaccine. A person who needs to be vaccinated against yellow fever has to visit a doctor at least 10 days before the travel. A single dose of attenuated (weakened) live-virus preparation subcutaneously takes effect within 10 days (4); immunity lasts for at least 10 years. After vaccination, everyone has to wait 30 minutes at the clinic, so that eventual (rare) allergic reaction can be treated.
Vaccination is required for all travelers entering India from endemic countries (arrival from or transit through an endemic zone in the previous 6 days), except for children below 6 months of age.
Yellow fever vaccination is generally effective and safe, but contraindications and side effects have to be considered.
Contraindications for yellow fever vaccine are:
- Age below six months
- Recent thymus disease, or removed thymus
- Allergy to eggs
- Impaired immunity: patients with AIDS (HIV positive persons without symptoms may be vaccinated if there is a high risk of infection), those receiving chemotherapy or radiation therapy, leukemia, lymphoma and other diseases with low immunity
Pregnant women should avoid yellow fever vaccinations, since adverse effects to the fetus are not known. If international travel requirements are the only reason for vaccination, a pregnant woman should obtain a waiver letter from the traveler’s physician to avoid vaccination.
Side effects of yellow fever vaccine are rare and may include:
- Mild headaches, myalgia, low-grade fever, starting within days after vaccination and lasting for 5-10 days
- Neurological complications (rare): encephalitis (seen only in first time recipients, mostly infants), Guillian-Barré syndrome and acute disseminated encephalomyelitis (5)
- Yellow fever vaccine-associated viscerotropic disease (YEL-AVD), a dangerous reaction affecting internal organs
- Allergic reaction with rash, itching, difficulty breathing, dizziness
If travelers from certain countries have not been vaccinated for yellow fever they are at risk of sending back to their country or they will be vaccinated in the point of entry and quarantined for 6 days. The incubation period of yellow fever is 3-6 days and international regulation accepts quarantine as the longest incubation period for that particular disease, in this case yellow fever and it is six days.
About Cholera Vaccination
Cholera is an acute diarrheal disease caused by the bacterium Vibrio cholerae. It usually causes a mild diarrhea, but may occasionally cause severe diarrhea leading to death from dehydration, if infected person is not re-hydrated promptly. Common sources of infection are contaminated water or raw or poorly cooked seafood, raw fruit and vegetables. Anyone losing a large amount of fluid because of diarrhea should see a doctor immediately to be properly hydrated. Antibiotic azithromycin may be used to shorten the course of disease (6).
Currently available cholera vaccines do not prevent transmission of infection. The World Health Organization (WHO) no longer recommends cholera vaccination for travel to or from cholera-infected areas.
According to Centers of Disease Control and Prevention (CDC) and World Health Organisation (WHO) , currently no country officially requires cholera vaccination for arriving travelers under International Health Regulations. Border officials in some countries may occasionally still ask for proof of vaccination if arriving from infected areas though (3).
c) Recommended Vaccinations (by CDC)
Vaccinations for India recommended by CDC (Center of Disease Control and Prevention) are the immunizations that a traveler should take before entry into a country, though they are not mandatory. These are for the safety of the traveler and strongly recommended.
Typhoid fever, caused by bacterium Salmonella typhi, is a life threatening febrile infection, acquired by fecal-oral route. Typhoid vaccination is recommended for those planning to travel into small cities and rural areas. Oral live attenuated, in capsule, dose 1 capsule alternate day for four doses, has to be taken a week before exposure (only after 6 years of age), immunity lasts for 5 years. Typhoid Vi capsular polysaccharide, single intramuscular injection has to be taken at least two weeks before exposure (only after 2 years of age), immunity lasts for 2 years. NOTE: Typhoid vaccines are only 50-80% effective, so prevention measures regarding food should be kept in mind.
Hepatitis A, caused by hepatitis A virus, is a fecal-oral infection of the liver, resulting in usually few weeks lasting fever, nausea, dark urine and jaundice. A hepatitis A vaccine (intramuscular) has to be taken two weeks before travel (only after 1 year of age). A hepatitis A/B combined vaccine (only after 18 years of age) consists of 3 intramuscular doses at 0, 1, and 6 months. Immunisation after hepatitis vaccination lasts for 5-12 years. Travelers, younger than 1 year, or allergic to vaccine, should receive a single dose of immune globulin (0.02 mL/kg), which provides protection against hepatitis A for up to 3 months. Side effects, if any are mild.
Rabies is a fatal encephalitis caused by Rabies viruses. After an incubation period (1-3 months) progressive muscular paralysis and death follow. Rabies vaccine is recommended for travelers planning to attend outdoor activities like camping or cycling where exposure to bite from rabies transmitting animals like raccoons, skunks, bats, foxes, cats, cattle, and dogs, is increased. Three intramuscular doses at day 0, 7, 21 or 28 should be given. Adverse effects of rabies vaccine are usually mild. Rabies vaccine cannot cause rabies. Post-exposure vaccine can be given regardless of interval from animal bite. Rabies immune globin (RIB) should be also always given in this case. Booster dose is advised every 2 years, if necessary.
Japanese Encephalitis Vaccine
Japanese encephalitis is caused by mosquito-borne Japanese encephalitis virus; the risk of exposure is mainly in rural areas. After incubation period of 5 to 15 days fever, gastrointestinal symptoms and headache usually appear, followed by generalized weakness, movement disorders or seizures. Japanese encephalitis vaccine consists of 3 subcutaneous doses 1 week apart, immunity lasts for 12 -18 months. Allergic reaction to vaccine is rare but may be strong, so observation for 30 minutes after injection is required.
Poliomyelitis, caused by poliovirus, is an acute infection affecting gastrointestinal tract and central nervous system, mainly in children. It is acquired by fecal-oral or oral transmission. Poliomyelitis vaccination is recommended to all non-vaccinated persons including infants after 6 weeks of age. Vaccination is generally safe (no known serious side effects) and effective.
While traveling to India a traveler should keep in mind certain things about India. Being a developing country and near the tropic India has a big burden of infectious diseases. Infectious diseases like malaria, dengue, typhoid and paratyphoid, diarrheal diseases, viral hepatitis, tuberculosis, cholera, diphteria, and so on, are endemic in India. Diseases like plague, water borne diseases, Japanese encephalitis are also not uncommon here. A foreign traveler visiting India should remember which disease is endemic in which area. If a person is visiting Kolkata or nearby parts of Eastern India, he should remember that these areas are endemic for diseases like cholera, typhoid fever, malaria, filaria, and other infections. In Northern India, dengue (transmitted by aedes mosquito) and amoebiasis are prevalent.
Vaccination Against Rotavirus for Children
Due to rotavirus diarrhea, every year about a half of million children die worldwide and another 2 million children are hospitalized. Administer the first dose of rotavirus vaccine (by oral route) between 6-12 weeks, not before 6 weeks of age and not later than 12 weeks. Second dose is given 4-10 weeks after the first dose. And the final dose 4-10 weeks after second dose, before 32 weeks and never after 32 weeks. Safety data are not sufficient beyond this range of 6-32 weeks.
Precautions for Traveller’s Diarrhea
Travelers diarrhea (TD) is mostly caused by enterotoxigenic Escherichia coli (ETEC) (1). It is seen among 20%-50% of the travelers from developed countries to developing countries. The symptoms of traveler’s diarrhea include sudden onset, increases frequency and volume of stool.
There may be over four watery stools per day. Other symptoms include nausea, vomiting, fever, abdominal cramps and bloating. The TD usually resolves within 2-3 days even if there is no treatment. The people from developing countries, including India, are already immune from frequent exposure and rarely get TD.
Some of the preventive measures that can be taken by the travelers include avoidance of undercooked foods and drinks from street vendors etc. A traveler should peel the fruits like bananas and oranges by himself. Also a traveler should carry his own drinking water or always drink branded mineral water.
- Risk to get infection in developing countries (pdrhealth.com)
- Vaccination recommendations for travellers and health care providers (cdc.gov/travel)
- Cholera vaccine not officially required (healthlink.mcw.edu)
- Yellow fever vaccine takes effect within 10 days (yellowfever.com.au)
- Neurological complications of yellow fever vaccination (cdc.gov/travel)
- Antibiotic azithromycin is effective in cholera (mayoclinic.com)