Measles risk for international travellers

Measles is a highly contagious viral disease, which, despite the availability of a safe and effective vaccine, remains an important cause of death among young children globally. Measles is spread by airborne or droplet transmission, and is considered one of the most highly communicable infectious diseases.

Measles is found throughout the world and is still common in many developing countries, particularly in parts of Africa and Asia. In recent years there have been several outbreaks of measles in other countries out-with Africa and Asia including Japan, Taiwan, Philippines, New Zealand, Thailand, Syria, USA and many European countries.

The recent outbreak of measles across many European countries serves as a reminder of measles risk in individuals who are not vaccinated or not fully vaccinated. Countries affected include Austria, Bulgaria, Czech Republic, France, Finland, Germany, Greece, Hungary, Ireland, Italy, Poland, Portugal, Romania, and the United Kingdom. In addition, neighbouring countries Albania, Belarus, Georgia, Russia, Serbia, Turkey and Ukraine have also been affected. During the summer, the likelihood of individuals coming into contact with measles is potentially higher due to people coming together in holiday destinations.

Measles is spread by coughing, sneezing, close personal contact or direct contact with infected nasal or throat secretions. The virus remains active and contagious in the air or on infected surfaces for up to two hours. It can be transmitted by an infected person from four days prior to the onset of the rash, to four days after the rash erupts. Symptoms of measles include erythematous maculopapular rash with fever and cough, coryza or conjunctivitis. Measles infection can be severe, with complications including blindness, encephalitis, severe diarrhoea and related dehydration, and severe respiratory infections such as pneumonia. Measles can be fatal.

Young children and adults aged 15 and over who were not given the measles, mumps and rubella (MMR) vaccine when they were young are at highest risk of measles and its complications. Any non-immune person, (one who has not been vaccinated with two doses of measles-containing vaccine), can become infected. The measles vaccine has been in use since the 1960s and is safe, effective and inexpensive, and has been included in the UK national schedule since 1968. The World Health Organization (WHO) recommends immunisation for all susceptible children and adults for whom measles vaccination is not contraindicated.

Advice for healthcare professionals to prevent the international spread of measles

The travel consultation provides healthcare practitioners with a valuable opportunity to ensure travellers are protected against the measles virus by: 

• Checking their vaccination status is up-to-date ensuring that they have received two doses of a measles containing vaccine in the absence of a history of prior measles infection. 
• Receiving at least one dose of measles vaccine at least 15 days prior to travel if they are uncertain of their measles vaccination status. 
• Measles vaccine can be co-administered with other vaccines recommended for travellers. Where yellow fever vaccine and MMR are both required, ideally they should not be given on the same day but given at least four weeks apart. Where protection is required rapidly, then the vaccines may be given at any interval. 
• Children who are travelling to measles endemic areas or to an area where there is a current outbreak, and have received one dose of MMR at the routine age, should have the second dose brought forward to at least one month after the first. If the child is under 18 months of age and the second dose is given within three months of the first dose, then the routine pre-school dose, a third dose, should be given in order to ensure full protection. 
• Measles vaccines are not recommended for pregnant women.

In the UK, MMR is usually given to infants at around 12 months of age, with a second dose given before school, to ensure best protection. In some cases, MMR can be offered to babies from six months of age, for example for travel to countries where measles is common, or to an area where there is a current outbreak. As the response to MMR in infants is sub-optimal where the vaccine has been given before one year of age, immunisation with two further doses of MMR should be given at the recommended ages.

Advice for travellers

All travellers should seek advice from their healthcare provider in advance of travel and be aware of the risk of exposure to measles virus as well as transmission and symptoms of the disease. 

Individuals travelling to countries where measles is common or where outbreaks are occurring are at risk of catching the disease if not fully protected. Two doses of MMR in a lifetime are needed for a person to be considered fully protected. Susceptible travellers may also risk exposing others to this highly infectious, serious illness either while travelling, or on return to the UK. 

Transmission of infection may occur between passengers who are seated in the same area of an aircraft, usually as a result of a cough or sneeze or by touch. This is no different from being close to someone in any other form of transport such as a bus or train.

An airline has the right to refuse travel to any passenger who is unwell and they suspect may be contagious. In order to minimise the risk of passing infections in an aircraft, passengers who are actively unwell, especially if they have a fever, should delay travel until they have recovered. Where an individual has travelled on an airline whilst infectious with measles, contact tracing of passengers will be carried out by public health authorities. 

Susceptible travellers who have returned from a country or area where measles is common should be alert for symptoms for three weeks after their last day of travel, usually developing symptoms about 10 days after they are exposed. However, it can take as few as seven and as many as 18 days for symptoms to develop. Measles symptoms include: 

• fever 
• cough, runny nose, and sore red eyes 
• general tiredness and feeling unwell 
• a spotty, non-itchy rash that starts on your head and neck and spreads to the rest of your body

Travellers who experience any of these symptoms, should not attend public places, such as work, school, healthcare services, shopping centres, nor use public transport. They should seek medical attention and, importantly, call ahead to the medical practice or emergency department to advise them of the symptoms, so that measures can be taken to limit their exposure to other people when they arrive.

Further advice relating to measles can be found on the TRAVAX (for health professionals) and fitfortravel (for the general public) websites.

Sources: TRAVAX and fitfortravel (both 11 July 2019)