Immunizations recommended for travel to Nepal

Introduction

Every decision to take a vaccine to prevent an illness is essentially a decision that the short term expense and slight discomfort (and slight risk) is worth the improved chance of avoiding an unpleasant or potentially fatal illness. The following recommendations are based on the advice of international agencies such as the World Health Organization and the Centers for Disease Control in the United States, coupled with our local experience. Vaccine recommendations occasionally vary from Europe to North America, usually in regard to the exact schedule of giving the vaccine. The results of vaccination can be the same with different schedules.

The protection that can be gained from vaccines varies from 50% to almost 100%. So remember that even if you have taken a vaccine you might still get the disease, although you will have greatly reduced your chances of getting ill.

1. For the Prevention of Hepatitis A:

Hepatitis A is a virus that infects the liver, causing a disease known as viral hepatitis. The disease is distinctly unpleasant, with profound nausea, loss of appetite, and weakness that can last for weeks. It can also be fatal on rare occasions. If you have had hepatitis A in the past, you will be immune for life and do not need the vaccine. The virus is passed in human feces, and is acquired the same way that you acquire traveler's diarrhea. Therefore, it is very difficult to avoid through safe eating habits.

Hepatitis A Vaccine: Highly effective and safe vaccine. Many brand names are in the  market e.g. "Havrix",  "Vaqta",  "Avaxim" and "Twinrix". Twinrix is a combined Hepatitis A and B vaccine. All of these vaccines are equally safe, effective, interchangeable and offer long lasting protection against Hepatitis A.  Most of these vaccines are given as a series of 2 injections except for Twinrix, the combined vaccine which is given as a series of 3. Havrix is given as a series of 2 injections, 1440 international units per injection of the vaccine is given on day 0, and then a booster is given from 6-12 months later, with adequate protection about 2 weeks after the first shot.

Gamma Globulin: This is rarely used nowadays as most travelers and almost all expatriates are getting immunized with the Hepatitis A vaccine. The vaccine offers protection even when given after exposure on account of the long incubation period of Hepatitis A.

2. For the Prevention of Hepatitis B:

Hepatitis B Vaccine: This is a well established vaccine with high safety and efficacy. Hepatitis B is spread through direct contact with infected blood or through sexual intercourse therefore, travelers to Nepal have very little chance of acquiring this infection through normal travel. Many long term travelers and foreign residents are recommended to take this vaccine. In addition, since there are no animal reservoirs of infection, an effort is being made to give hepatitis B vaccine to all humans, which would eventually eliminate the disease from the world, much as smallpox was eliminated by a vaccination campaign in the 1970's. The regimen for hepatitis B vaccine is an initial injection followed by boosters at one month and six months.

3. For the Prevention of Typhoid Fever:

Typhoid fever is a prolonged febrile illness caused by infection with Salmonella typhi bacteria. An almost identical illness, called paratyphoid fever, is produced by Salmonella paratyphi. Infection with either organism is referred to as "enteric fever." The organisms are passed in human feces, and acquired by eating contaminated food or water. The disease is rarely fatal in foreigners, and can be treated with antibiotics. However, it makes you very sick and complete recovery can take several weeks. Therefore, we recommend taking a vaccine to prevent typhoid fever, which is an extremely common illness in Nepal (about 1 in 300 unvaccinated travelers get the disease). There are currently two different typhoid vaccines on the market - an oral typhoid vaccine using live organisms, and a capsular polysaccharide injectable typhoid vaccine.

Capsular Polysaccharide Typhoid Vaccine (Typhim Vi): This vaccine consists of a highly purified coating of the Salmonella typhi bacteria. Because the whole bacteria is not injected, side-effects are minimal. It consists of a single injection of the vaccine with protective efficacy around 80%, with boosters required every two years.

4. For the Prevention of Meningococcal Meningitis:

Meningococcal Meningitis: Centers for Disease Control (CDC) in the U.S. has stopped recommending this vaccine since 1998 for travel to Nepal, but this is a very safe vaccine with efficacy lasting 3-5 yrs. Meningococcal meningitis is a severe bacterial infection of the lining of the brain which is usually rapidly fatal without treatment. There was an epidemic of meningococcal meningitis in Nepal in 1983 with 6 foreign trekkers contracting the disease leading to the original recommendation for this vaccine for all travel to Nepal. Meningitis is spread through coughing or sneezing in a closed environment, with the bacteria entering your body through the nose and mouth. The vaccine is safe, 90% effective, and protection from a single shot lasts three to five years in people over age five, and two years in children under five.

5. For the Prevention of Japanese Encephalitis:

Japanese Encephalitis (JE) Vaccine: JE is caused by a virus carried by culex mosquitoes in rural areas of southern Nepal or the Terai. This virus can cause a severe and often fatal infection of the brain. JE has now been found to exist in the Kathmandu valley since 1996. It is difficult to calculate the risk in foreigners since there has not been a single case of JE in a foreigner in Nepal. The actual risk probably is extremely low. Visitors who will spend less than a month in Nepal are the lowest risk individuals and we are not recommending vaccine to this group. Visitors staying more than a month in Nepal particularly if visiting in the post-monsoon months of August-October and all residents of the Kathmandu valley are recommended to receive immunization against JE. We continue to strongly recommend the vaccine for persons living in the Terai. Casual visitors to the Terai probably do not need the vaccine. The full series of the vaccine consists of 3 shots given on days 0, 7, and 28. If time is short, the 3 shots can be given one week apart. One should have a booster every 3 years, if risk persists.

6. For the Prevention of Rabies Encephalitis:

Rabies Vaccine: Rabies virus is transmitted by the bite/scratch of infected animals or from saliva contact with mucous membranes. The disease is present throughout Nepal, India, and Tibet and dogs account for >96% of human cases. The rabies virus, once injected by a bite, travels slowly to the brain over a period of weeks to years, causing a fatal encephalitis. Because of the delay between the bite and clinical illness, rabies vaccine and immunoglobulin can be injected after a bite to prevent the person from developing a rabies infection. This post-exposure series offers essentially 100% protection but it does take a month to complete the five shots plus the initial injection of human rabies immune globulin (HRIG), which is very expensive ($600 to $1000 depending on your body weight). For this reason, long-term travelers or foreign residents often take a pre-exposure series, consisting of 3 shots on days 0, 7, and 28. These pre-immunized individuals require only two booster shots 3 days apart,if they are bitten by an animal. The risk of being bitten by an animal in our recent study was 2 out of 1000 persons for one year of travel with triple the risk if one was an expatriate resident living mainly in Kathmandu. Trekking was not associated with increased risk of exposure. The decision to take pre-exposure series is up to the individual since effective post-exposure therapy exists. However, we highly recommend the pre-exposure series for children, who may not report to their parents every contact with a stray animal or someone's pet. We recommend the first booster in one year then every 3 years.

7. For the Prevention of Tetanus:

Tetanus Vaccine: Tetanus bacteria can infect small wounds and cause a fatal infection. The risk is the same throughout the world. For this reason, most people have received tetanus vaccine (usually mixed with diphtheria vaccine for greater effect), since early childhood. Boosters should be obtained every 10 years, and foreign travel is an opportunity to review one's tetanus vaccine status.

8. For the Prevention of Polio:

Polio Vaccine: Polio virus used to be endemic in Nepal and mass vaccinations of children under the age of 5 years against Polio have been completed by WHO and active surveillance for cases is going on now. Nepal has not yet been declared polio-free. Almost all tourist and foreign residents have been vaccinated against this disease in childhood. However, this initial immunity can decrease over the years, and one booster as an adult is recommended if you travel to developing countries. The booster can be with the oral vaccine if you have previously been immunized. If you have never been immunized against polio, you need to get the injectable inactivated vaccine.

9. For the Prevention of Cholera:

Cholera Vaccine: The risk of cholera to the foreign traveler or resident in Nepal is close to zero. Cholera is mainly spread by heavily contaminated water, or by certain sea coast animals that concentrate the bacteria (such as oysters). If you are conscientious in not drinking untreated water (or milk, which is often contaminated with water), you will have almost no chance of getting cholera.

10. For the Prevention of "The Flu."

Influenza Vaccine: Influenza, or "the flu," is a viral illness that causes fever, muscle aches, cough, and misery for a number of days. The attack rate is high among travelers, who often are more vulnerable due to the stress of travel, and the congestion of many forms of public transport and restaurants. The vaccine consists of killed particles of three different strains of influenza, and can greatly diminish your risk of getting sick with the flu. Although not routinely recommended to travelers, it is a safe vaccine that may save you a week of discomfort on your holiday, or prevent you being ill during a brief working trip to Nepal or India. A single injection offers protection for about 6 months to one year. New vaccines are formulated each year based on world-wide reporting of which flu is going around.

Malaria in Nepal – advice for the short-term traveler

Introduction

Malaria is a parasitic infection of the blood transmitted by night biting, female Anopheline mosquitoes. Around the world it kills about two million people (WHO) each year and in many countries the situation is getting worse. With 50 million people traveling from the developed to the developing world each year, it is also a great threat to travelers. In the UK alone, over two thousand travelers return each year with malaria, must of it acquired in sub-Saharan Africa. Approximately 10 returning travelers die from malaria each year in the UK alone

Avoiding malaria is probably the most time consuming and confusing health issue that the would-be traveler faces. In South Asia alone the risk varies from extremely high to zero with widespread resistance to commonly used drugs. Malaria is transmitted in some large cities; most other cities are malaria free. In some areas malaria is seasonally transmitted, in other’s it is transmitted all year round.

The risk to travelers cannot automatically be assumed to be the same as the risk that exists for the local population and the risk to more vulnerable travelers, such as pregnant women and young children must be individually assessed. In addition to this there is a bewildering array of drugs that may be used to prevent the traveler from contracting malaria and to make matters worse, doctors seem unable to agree on a particular strategy for a particular travel destination.

With such a confused picture and seemingly complete lack of consensus, quite often travelers decide to take nothing at all and leave themselves vulnerable to a potentially fatal infection. The following article is designed to help travelers to Nepal gain a better understanding of the situation that exists here in Nepal and so be in a good position to decide on what strategy they should use to avoid getting malaria.

A brief history of malaria in Nepal

For malaria transmission to take place, certain conditions need to exist. The habitat of the “transmission area” must support the lifecycle of the Anopheline mosquito. The ambient temperature must be high enough to allow the parasite to develop in the body of the infective mosquito and there must be a “pool” of infected people in the transmission area that allows the mosquito to pass the disease from an infected person to a previously non-infected person.

In Nepal, conditions for the transmission of malaria only exist in certain areas of the country, the low-lying southern belt of land known as the Terai and to a much lesser extent, the middle hills below about 1000 meters elevation. Up until 1960 the inhabitants of the Terai were almost exclusively from a single group known as the Tharu. The Tharu people of Southern Nepal are known to have developed a genetic resistance to malaria, allowing them to thrive in an area that was ill famed for being heavily infected. By 1960, after an extensive eradication campaign, the Terai was almost freed of malaria, allowing non-Tharu people to safely populate the region. Subsequently, malaria has crept back into the Terai region and the rate of malaria transmission has slowly increased to its present level. At present the "roll back malaria" campaign is attempting to control the current level of malaria transmission using pre-season spraying of mosquito habitats and education of the local population in bite avoidance.

The current situation

Malaria is transmitted in all areas of Nepal except the eleven Himalayan districts and the three districts that make up the Kathmandu valley. In most of the remaining districts, which includes the middle hills and some of the districts on the Terai, the transmission rate is so low as to pose very little threat to the populations of those districts. The majority of malaria transmission in Nepal occurs in only 12 districts and these have been labeled "priority" districts. They are prioritised not only for the higher rate of malaria transmission that occurs within them, by also for the higher rate of P. Falciparum malaria transmission (except for Kavre). These districts are: Dadeldhura, Kanchanpur, Kailali and Bardia in the far western Terai; Nawalparsi in the central Terai; Sindhuli, Mahottari and Dhanusha in the east central Terai and Morang, Jhapa and Ilam in the far eastern Terai.

The twelfth priority district is Kavre, immediately east of the Kathmandu valley. In particular the Panchkal valley within Kavre sees high rates of transmission of P. Vivax malaria. (See note below on Kavre district).

About 10,000 cases of malaria are reported each year in Nepal, with over 90% being of the species Plasmodium Vivax, which causes a relatively benign form of malaria in otherwise healthy individuals. The remainder of cases Plasmodium Falciparum malaria, a potentially dangerous infection. In addition, the transmission of malaria is very seasonal, with most transmission occurring between June and August, and very little occurring in the winter months between November and March.

The risk to tourists

The risk to tourists can be assessed in two ways. Firstly by knowing the number of tourists that actually contract malaria from a visit to Nepal. To know this we need to know the number of tourists that present with malaria in Nepal itself and also those that return to their home countries having acquired malaria in Nepal. Since 1985 there have been three confirmed cases of malaria in travelers returning from Nepal to the US, one of this group also traveled in south east Asia. In the UK, since 1987 there have been seven cases of malaria in travelers returning from Nepal. Detailed information as to the origin of these infections is not known and it may be that they also traveled in India. No other information regarding returning travelers to other countries is known except for Israel, where there have been no reported cases of malaria in travelers returning from Nepal.

Lastly, in 1998 a US Peace Corps volunteer developed malaria in the month of July. The volunteer was resident on the Terai and had spent some time in the far-eastern Terai just prior to being diagnosed. It is thought that this is where he contracted malaria. The case was treated as Falciparum malaria, making him the first foreigner in Nepal to have contracted P. Falciparum malaria since the CIWEC clinic first began recording cases. This was never confirmed and it is quite possible that he had P. Vivax malaria.

These very low numbers of cases should be placed in some context. In 1998-1999, about 60,000 permits were issued to visitors to the national parks on the Terai. 50,000 of these were for the Chitwan Park alone. In addition, many travelers visit Lumbini, Janakpur and other sites of cultural interest for which no permit is required. The number of travelers arriving from India via the Terai is also not included in this figure. So despite the very large numbers of visitors to the Terai each year, the number of cases of malaria acquired directly as a result of one of these visits is extremely low. It is likely that a brief visit of two or three nights to the Terai in the most popular months of the year has never resulted in a malaria infection, but the data on this is lacking. The factors contributing to this are probably many and one may be that all the visitors are using prophylaxis and so are not getting malaria.

So what should you do?

Irrespective of what pills anybody tells you to swallow, you must take measures to avoid being bitten by mosquitoes. This is most important in the prevention of all mosquito borne diseases, not just malaria and is something that should be deeply imprinted in the minds of all travelers, wherever they happen to be.  Bite avoidance (personal protective measures or "ppm's") is most important between dusk and dawn, when most mosquitoes are active and searching for blood meals. It may sound obvious but here it is again:

• Cover up. Use light, long legged trousers and long sleeves. Some experienced travelers even impregnate their evening clothes with insecticide.

• Use insect repellants. DEET containing repellents are very effective.

• Bed nets, especially if impregnated with insecticide, are very effective at protecting you while you sleep.

• Burn coils or use vaporizing mats in your room at night.

Malaria prophylaxis – should you take it?

Malaria prophylaxis (pronounced pro-fee-lak-sis) refers to the drugs that are taken to prevent malaria and is somewhere between a vaccine and a treatment. Like all vaccines, it is a balance of risks. In this case it is the risk of contracting malaria versus the risk of side effects from the prophylaxis. Like all treatments, there are various options depending on the needs and condition of the traveler. The above ten points summarizes the risk to visitors in Nepal and it is clear that the risk of contracting malaria while on a brief visit is extremely low.

Travelers at special risk from malaria and those with other medical conditions

·       Pregnant women:  pregnant women are at great risk from severe malaria and should avoid visiting areas of malaria transmission if at all possible. If a visit to a high-risk area (e.g. a priority rural area during the early monsoon period) is absolutely necessary, prophylaxis should be taken. (See below). Chloroquine and Proguanil have a long safety record in pregnancy but Proguanil use should be supplemented with Folic acid 5mgs daily. Mefloquine should not be used in the first three months of pregnancy and Fansidar is also not to be used by pregnant women.

·       Young children:   young children are not necessarily at greater risk of contracting malaria, but they have a habit of getting sick rapidly. Looking after a sick child can be a nerve racking experience, especially if they have a potentially dangerous illness. Making a diagnosis can also be difficult, especially in babies and infants. We would advise having a low threshold for giving a young child prophylaxis if visiting a high-risk area were essential. Chloroquine is safe to give young children and comes in a liquid suspension (the only prophylactic that does) but its taste is incredibly bitter. Mefloquine can also be used if the child weighs more than 5kgs. This is a convenient once weekly dose that can be crushed and added to food. Doxycycline must not be given to children under the age of 12 years. Bed nets, mosquito coils and insect repellents are essential items when traveling with children.

·       Anybody without a spleen:   the spleen is situated under your ribcage in the left side of your chest, just beneath the diaphragm. Its job is essentially to clean the circulating blood, removing old or damaged cells as it does so. As a result it has an important job to do when the red cells are infected by malaria parasites. Without it, malaria infections can progress rapidly so those who have no spleen (it is removed usually as a result of trauma) should have a low threshold for taking prophylaxis and be meticulous in avoiding mosquito bites.

·      Those with epilepsy:  those with epilepsy or other seizure disorders should avoid both Chloroquine and Mefloquine. Alternatives are to use Proguanil alone or Doxycycline at a higher dose if anti-convulsant medications are being taken. Fansidar is safe as standby treatment but should not be used as prophylaxis.

·      Those with liver or kidney disease:  Proguanil may not be used by those with kidney disease. Chloroquine, Mefloquine and Doxycycline are safe. Those with mild liver dysfunction may use Chloroquine and Proguanil, Mefloquine and Doxycycline should be avoided. Those with severe liver dysfunction may only take Proguanil and so should avoid travel to transmission areas if at all possible.

CIWEC Clinic guidelines on malaria prophylaxis in Nepal

1.  Situations for which prophylaxis is NOT routinely recommended at any time of year:

·       Visitors to Kathmandu arriving by air and remaining in the Kathmandu valley or trekking in the hills above Kathmandu.

·       Visitors to Pokhara, traveling overland from Kathmandu having arrived by air and trekking in the hills above Pokhara.

·        All other trekkers and mountaineers arriving in Kathmandu by air who reach their start point without visiting the Terai.

·        Visitors rafting high altitude rivers e.g. the Bhote Khosi.

2.   Situations for which prophylaxis IS routinely recommended:

·       Visitors to the "priority" districts during the summer months (June to September) intending to sleep in rural areas for longer than one week. This includes visitors to Bardia and Suklaphanta national parks and the rural areas surrounding Janakpur and Nepalgunj during the summer months.

3.      Situations where the risk of contracting malaria is extremely low but for which prophylaxis is NOT routinely recommended:

·       Healthy individuals not at special risk (see 'Travelers at special risk') visiting either Bardia or Chitwan national parks between October and May and returning immediately to within quick access to competent medical help (Kathmandu or home country).

·        Healthy individuals not at special risk (see 'Travelers at special risk) visiting urban areas of the Terai between October and May who are then returning directly to within quick access to competent medical help (Kathmandu or home country).

·        Healthy individuals not at special risk (see 'Travelers at special risk'), rafting rivers in the middle hills between October and May, where the pull out point is on the Terai, and returning directly to within quick access to competent medical help (Kathmandu or to your home country).  This includes those going on to visit one of the national parks during the winter months, having completed a river-rafting trip.

4.   Situations for which the risk is extremely low and prophylaxis should be considered:

·       Visitors to the western Terai who are then traveling on to remote areas for longer than a week. Typically this includes visitors to Humla (including Mt Kailash trekkers), Jumla or Dolpa regions who are sleeping overnight on the edge of Bardia district (Nepalgunj), especially during the summer months (June to September) when these high treks are most popular.

·      Visitors to the eastern Terai who are then traveling on to remote areas for longer than a week. Typically this includes visitors to Kanchenjunga region (especially during the summer months (June to September) that overnight in Biratnagar, Dharan or Dankuta before starting a long trek. This also applies to visitors traveling down to the trek start point from Kathmandu by road, especially those staying overnight on the Terai during the journey.

Kavre District: Kavre is the district immediately east of the Kathmandu valley and within this district is a relatively low-lying valley named the Panchkhal valley. Within this valley there is a fairly high transmission rate of P. Vivax malaria. For this reason and because of its proximity to Kathmandu it has been labeled a "malaria priority district". Tourists very rarely stay in this district and there are no tourist lodges in the Panchkhal valley. Travelers to Tibet or the resorts near the Tibetan border ("The Last resort", "Borderlands" etc) and those rafting the Bhote Khosi river will pass through this valley during their journey. Transiting Kavre does not constitute a risk of acquiring malaria, nor does staying in the town of Dhulikhel situated immediately west of the Panchkhal valley. Dhulikhel is on the ridge between Panchkhal and Kathmandu and at considerably higher altitude than both places.

Prophylaxis choice for travelers "at risk" in Nepal

Having established that you are a traveler "at risk" by either the timing and duration of your visit or by the type of traveler you are, you need to choose a malaria prophylactic to use in addition to bite avoidance. The vast majority of malaria in Nepal is P.Vivax malaria and is sensitive to Chloroquine. There is a tiny chance that a brief visit to the Terai while in transit will result in infection with P.Falciparum malaria, even though to our knowledge it has not yet happened. But it is for this small chance when going into a remote area for which precautions need to be taken. Here are your choices:

      Chloroquine (Avioclor, Nivaquine) 300mgs weekly and Proguanil (Paludrine) 200mgs daily, taken two weeks before entering a transmission area and continued for four weeks after leaving a transmission area. In the case of trekkers transiting in the Terai, this regime should be continued until four weeks have elapsed OR the trek has finished and you have returned to within quick access of competent medical help, whichever is latest. This regime should give adequate protection against P.Falciparum malaria, even low-grade Chloroquine resistant strains. Chloroquine alone may not protect against certain strains of resistant P.Falciparum malaria.

Chloroquine is not suitable for those with a history of epilepsy/convulsions, those with psoriasis (may worsen this skin condition) and should not be taken at the same time as intra-dermal rabies vaccine is being given (reduces vaccine effectiveness). It does not interfere with the standard 1.0ml intramuscular rabies vaccine. It is safe for use in pregnancy and may be taken by young children.

      Mefloquine (Lariam) 250mgs once weekly, taken at least two and a half weeks before entering a transmission area and continued for four weeks after leaving a transmission area. Mefloquine is more effective against resistant P.Falciparum malaria than Chloroquine alone, but has a slightly higher rate of side effects, especially neuropsychological side effects, even though these are rare (about one in ten thousand users). It is safe for use by young children and in pregnancy after the first three months. Women of childbearing age are advised not to take Mefloquine without using adequate contraception methods. Mefloquine is not suitable for those with a history of epilepsy or convulsions and those with neuropsychiatric disorders. It should be stopped if anyone using it experiences nightmares or panic attacks 

      Atovaquone (250mgs) and Proguanil (100mgs) (Malarone): a new, relatively safe (so far) effective but expensive malaria prophylactic licensed for use as such in the UK, US and Denmark, with more countries expected to license its use in the near future. It is especially useful in areas where Mefloquine resistance has developed (not the case in Nepal) or in travelers who are unable to tolerate other prophylactic drugs. As a "causal" prophylactic it kills malaria parasites in the early stages of infection as they are entering the liver. This means that it only needs to be taken for a week following exposure and not for four weeks as do the other drugs. This makes it cost effective for short exposures or repeated exposures. It is taken daily at the above dose (one tablet) with food or a milky drink starting a day or two before entering a malaria endemic area and continued for seven days after leaving an endemic area. Its use in pregnant women is not licensed but there is a pediatric formulation available. No dose adjustment is required for elderly travelers, even those with mild liver or kidney disease.