Let’s Understand Measles

What Is Measles?

Measles is an acute respiratory viral infection. It is a reportable (notifiable) disease, which means that any confirmed or suspected case must be reported to Public Health. If you think your child may have measles, contact your paediatrician right away. They can advise you on what to do, guide you through suspected cases, and help you get in touch with Public Health.

Many people believed measles had been eradicated or nearly eliminated from modern medicine because it can be prevented with the MMR vaccine. However, with declining vaccination coverage in many parts of the world, outbreaks have been increasing. This article aims to help you better understand measles and highlight the importance of vaccination.

In 2000, the Centers for Disease Control and Prevention declared measles eradicated in the United States. However, recent outbreaks have emerged in several states, a trend closely linked to reduced vaccine coverage. In 2025, there have been 1,753 reported cases in the United States (as of 19th November 2025), 92% of these are in unvaccinated individuals or those with unknown vaccination status. 12 % required hospitalisation, and tragically, three patients died, two unvaccinated children and one unvaccinated adult.

Measles outbreaks have also been recorded in other regions, including Canada, Mexico and the United Kingdom.

Measles in the Cayman Islands

There have been no measles cases in the Cayman Islands since 1990. Currently, 90% of 15-month-olds have received their MMR vaccine, and coverage increases to 97% by ages 4–5 (Public Health Alerts – HSA, 2023).

However, with rising outbreaks in the US and other countries frequently visited by Cayman residents, it is essential to remain vigilant, recognise the symptoms and ensure vaccination, particularly if doses were missed due to the pandemic or recent relocation.

How Measles Spreads

Measles is highly contagious. It spreads through airborne particles when an infected person breathes, coughs or sneezes. The virus can survive in the air of an enclosed space for up to two hours, meaning one infected individual can expose many others, typically 12 to 18 people.

It can also spread through direct contact with infected nasal mucus or saliva. Around 90% of non-immune individuals will develop measles following exposure.

Recognising Measles

The main symptoms of measles include:

• Fever
• A red, blotchy rash
• Cough, runny nose and red eyes
• Koplik spots (tiny white spots inside the mouth), though not always noticed

Symptoms are more concerning in anyone who is unvaccinated, has travelled to an area with a recent outbreak, or has been exposed to measles within the past 21 days.

Measles has an incubation period of 10 – 14 days, though it can range from 7-21 days. Individuals are contagious from four days before the rash appears until about four days after.

If you suspect measles, remember that it is a reportable disease. Contact your paediatrician immediately, who can then assist you in contacting Public Health.

How Measles Is Tested For

Diagnosis is usually confirmed through:

• PCR testing of a throat or nasopharyngeal swab, or
• Blood tests detecting measles-specific IgM antibodies.

Public Health will guide testing and isolation procedures if measles is suspected.
Complications from Measles

Children under 5, adults over 20, pregnant individuals, and those who are immunocompromised are at the highest risk of complications.

Common and serious complications include:

• Hospitalisation (around 1 in 5 children with measles)
• Pneumonia (1 in 20)
• Encephalitis – inflammation of the brain (2 in 1,000), which may cause convulsions, long-term disability, or death
• Death – around 3 in 1,000 people with measles

Measles can cause pre-term labour in pregnant women and may result in babies who are small for gestational age.

A particularly severe long-term complication is subacute sclerosing panencephalitis (SSPE), a fatal degenerative brain condition that appears 7-10 years after measles infection. It occurs in approximately 5 in 10,000 children who had measles.

Preventing Measles: Vaccination

Prevention is straightforward: the MMR vaccine.

The MMR vaccine protects against measles, mumps and rubella. It is normally given around one year of age. In Cayman, the first dose is administered at 15 months, with a second dose given at least three months later, typically at 18 months.

The MMR vaccine is highly effective:
• 93% protection after one dose
• 97% protection after two doses

It is safe and can be given to older children and adults who missed doses earlier in life.

Possible Side Effects

The MMR vaccine is extremely safe. As with all vaccines, rare side effects can occur.

Some children may experience mild, temporary symptoms such as:

• A mild rash or fever between days 6-10 (representing a very attenuated, non-contagious vaccine response)
• Swollen glands around three weeks after the vaccine (related to the mumps component)

These vaccine-related symptoms are not contagious, and simple treatment such as paracetamol can help with fever or discomfort.

A rarer side effect is febrile seizures, occurring in about 1 in 1,000 children, typically 14 days after vaccination. These are brief, settle quickly, and do not increase the risk of epilepsy.

Who Should Not Get the MMR Vaccine

The only individuals who should not receive the MMR vaccine are those with severe immune deficiency.

A common misconception is that the MMR vaccine cannot be given to those with egg allergies. In fact, MMR is safe even in children with severe egg allergy.

Stay Informed and Protected

Measles is highly contagious but preventable. By understanding how it spreads, recognising the symptoms, and keeping up to date with the MMR vaccine, we can protect ourselves, our families, and our communities. Even in places like the Cayman Islands, where measles has been absent for decades, vigilance and timely vaccination remain key to staying safe.

Sources

• Stoneman, K. (2025). Measles. JAMA. https://jamanetwork.com/journals/jama/fullarticle/2837762
• BBC News article. https://www.bbc.com/news/articles/cy7e2lv4r8xo
• Health Services Authority (Last updated 2023), Cayman Islands. Measles Outbreak Advisory. https://www.hsa.ky/articles/measles-outbreak-advisory
• Optimal Healthcare Ltd. Clinical Services and Vaccination Resources from Dr Sara Watkin. https://optimal.ky/clinical-services/resources/
• World Health Organization. Measles Fact Sheet. https://www.who.int/news-room/fact-sheets/detail/measles
• Centers for Disease Control and Prevention (CDC). Measles Cases and Outbreaks. https://www.cdc.gov/measles/cases-outbreaks.html