Twelve laboratory-confirmed cases of circulating vaccine-derived poliovirus type 1 have been diagnosed since late April in Port Moresby (1 case) and in the provinces of Eastern Highlands (4 cases), Enga (2 cases), Madang (2 cases), and Morobe (3 cases). The most recent was on August 2. One clinical case of polio often represents hundreds of infections in the population with out symptoms. Risk to travelers is negligible but an adult booster of inactivated polio vaccine for all travelers going there is recommended (in addition to a past a primary series).
Papua New Guinea has not had a case of wild poliovirus since 1996, and the country was certified as polio-free in 2000. In response to the cases 4 rounds of large scale immunisations campaigns have been started to vaccinate children under 5 years.
Many travellers think that preparation for a healthy trip just involves vaccinations. In reality, the vaccine preventable diseases are a much less frequent cause of ill health than diseases we cannot vaccinate against such as diarrhoea, skin problems, malaria and dengue. Similarly, deaths during travel are most commonly the result of heart attacks or accidents, not vaccine preventable diseases.
A recently updated graph of vaccine preventable diseases still puts influenza at the top of the list for vaccine preventable illnesses in travellers (1 in 100). It is particularly sensible for those travelling in groups, on cruise ships and the elderly to have one before travel. Animal bites with a risk of rabies (3 in 1,000) are next then typhoid in South Asia (2 in 10,000) followed by hepatitis A (1 in 10,000). Tick borne encephalitis, measles and hepatitis B are the next occurring in 3 or more per 100,000 travellers to risk areas. While the risk of yellow fever has traditionally been low in travellers this has changed with around 30 cases seen in the past 2 years during outbreaks in Angola and Brazil.
Make sure you have had 2 doses of measles vaccine (MMR) before travel as cases are up in many areas around the world. If you were born prior to 1969 you should be protected against it as the virus was circulating prior to then. Those born since then should be sure they have had 2 doses as one does not protect everyone. Currently the MMR vaccine is given at 15 months and 4 years of age. Unfortunately, the false autism scare seriously knocked confidence in the vaccine so many people were not vaccinated and in order to keep measles rates low vaccination rates of 95% are needed. The vaccine is a live vaccine so pregnant women and those with weakened immune systems should not have it. Live vaccines should be given together or 28 days apart so don’t have it just before getting a yellow fever vaccine or the shingles vaccine.
Venezuela has recorded 1613 measles cases and 44 deaths this year and other countries in Latin America have cases linked to Venezuela. For example, Brazil has had nearly 700 cases in 2018 and Argentina has had cases despite not having any local measles since 2000. This year in the UK 757 cases of measles have been reported compared with 274 cases reported in the whole of 2017 and 3 deaths due to measles have been reported in France this year.
Returning travellers bring measles back to their home countries and start out breaks. This year an unknown person must have passed through Queenstown airport when infectious with the virus as a cluster of cases among people who had been in the airport at the same time as each other developed measles. The same thing has been noted in Japan a number of times recently including 91 cases diagnosed in Okinawa after an infectious person visited the island.
The past influenza season in the northern hemisphere saw very high rates of illness, hospitalisations and deaths. A recent study on influenza showed that on average 1 in 5 unvaccinated children and 1 in 10 unvaccinated adults are infected with seasonal influenza annually. Half of those infected have typical symptoms of influenza. Rates are highest in children, followed by older people, and lowest in adults. Vaccine efficacy varies considerably each season depending on if the vaccine matches the circulating strains well or not. The match for the past northern hemisphere vaccine was not good so protection was estimated to be only 36%. We have a different component in our vaccine for this season and hope it will match the strains we get. I encourage you to have an influenza vaccine and also remember that in the tropical parts of the world influenza circulates year round.
It’s better not to have a live vaccine such as MMR or Zostavax in the month prior to having a yellow fever one
It is better to have live vaccines on the same day or a month apart or else the effectiveness of them may be reduced. Yellow fever is a live viral vaccine and so are the Measles Mumps and Rubella (MMR) and the shingles vaccine (Zostavax). If having either of them please do them at least month before or after your yellow fever one or schedule an appointment with your GP on the day you are coming for your yellow fever one.
Zostavax, a vaccine to reduce the risk of shingles and the pain that may follow shingles became funded in New Zealand from 1 April for those aged 65 years or older so many people are being offered it by their GP practice when having their annual flu one. It is a live vaccine that contains weakened varicella zoster virus (the virus that causes chicken pox and shingles). MMR is also being recommended increasingly as outbreaks occur both here and overseas because of low uptake of the vaccine in some groups and some countries. Remember if having either of them and needing a yellow fever one also think about the timing before going ahead.
Recently WHO proposed new guide lines about rabies vaccinations both before travel (preexposure) and after a mammal bite (post exposure.) They have shortened pretravel/ preexposure vaccinations from 3 doses over a month to 2 doses a week apart. This is cheaper obviously and uses less vaccine (important factors in WHO’s considerations) and easier allowing people to do the 2 doses in only a week rather than a month. The doses may be intramuscular or into the skin (intra dermal) with intradermal needing injections at 2 sites each dose. At the recent Asia Pacific Travel Health Conference in Bangkok it was interesting to hear how other countries are responding to the proposed change. There remains anxiety that while 2 doses get people protected for their upcoming trip the information on how long in to the future people will be boostable (respond to boosters after a bite) is uncertain. It seems at this time doctors in America and UK will continue to give 3 doses pretravel so that people can be sure they are protected for future trips.
There is a network of clinics around the world seeing people who are unwell during or after travel. Information about the health problems travellers need to be seen for at these clinics is collected and analysed. It is notable that 74% of those needing to be seen for medical care after mammal bites had been bitten in Asia (42% in South East Asia and 32% in other parts of Asia.) This compared with only 9% in Africa and 7% in Latin America. Top countries were Thailand, Indonesia, Nepal, China and India. While the data probably partly reflects the numbers of travellers to the different destinations and where the clinics are situated it also clearly shows the higher risk of mammal bites in Asia than other regions. Another study showed that travellers from NZ and Australia departing from Bangkok airport had been bitten more often than people from other countries. This probably reflects that fact that we are not used to thinking about rabies as we are fortunate not to have it here. Remember that mammal bites in most countries are a big nuisance and really try not to play with dogs, monkeys or other mammals. It is a shame that pretravel rabies vaccinations are expensive but they make a mammal bite much less stressful. Certainly consider getting them when travelling to Asia.
Last March I wrote a blog about increased numbers of cases of yellow fever in Brazil including close to Rio de Janeiro. This year Sao Paulo is seeing cases of yellow fever in monkeys and humans and vaccination is now recommended for travellers to all parts of Rio de Janeiro and Sao Paulo states including the urban areas. More than 180 laboratory-confirmed human cases of yellow fever (including 76 deaths) have been reported in the states of São Paulo (80 cases), Minas Gerais (> 45 cases), and Rio de Janeiro (15 cases) and in Distrito Federal (1 case) since July 2017. This is a big increase over normal numbers of cases. In addition, more than 250 confirmed cases of yellow fever in nonhuman primates have been reported since October 2017 throughout forested areas of São Paulo City and in expanding areas of São Paulo Metropolitan Region. Because of this many parks including the zoo and botanical gardens in São Paulo City are closed. Brazil has launched a massive vaccination campaign and hope to vaccinate almost 24 million people in the states of Rio de Janeiro and Sao Paulo in the hopes of preventing an urban outbreak.
Dengue cases are increased In Samoa, American Samoa and French Polynesia currently. So, remember to take repellent and use it to prevent day time mosquito bites when visiting these countries. According to Samoa's Ministry of Health, more than 1,500 suspected and confirmed cases of dengue fever (serotype 2), a significant increase over average incidence, occurred from August to November and high numbers are still being seen. Cases are particularly on Savai'i and Upolu islands, mainly in Apia and the districts of Gaga'emauga and Tuamasaga (Upolu Island). The last dengue outbreak (serotype 3) occurred in 2015-16. In French Polynesia it is dengue 1 circulating currently.
The Pacific has the climate and environment for mosquitos to thrive and movement of people ensures the different strains of dengue virus are introduced regularly to different countries in the region. Dengue, chickungunya and zika are all transmitted by the same day feeding mosquitos which are common in the Pacific so always remember to try and prevent mosquito bites when there.
There have been more cases of plague than usual in Madagascar recently. Low risk always exists throughout most of the country including Antananarivo and Mahajanga but mainly in the central and northern highlands above 800 m. Transmission occurs throughout the year but the highest activity occurs from October to January. There are usually only about 300 cases per year but this year there have been more than 2,300 cases (including 207 deaths) since late August. Cases have been in numerous cities and districts mainly in Analamanga Region including Antananarivo and the city of Toamasina. The last confirmed case was reported on November 21. Public health measures have been increased and screening of departing travellers at airports started. Some countries are screening those arriving from Madagascar. Countries in the surrounding region have had help from WHO to be prepared for cases. The risk to travellers to Madagascar is very low but they should avoid contact with potentially infected rodents and their fleas as well as sick people especially those with a cough.