Measles – An Ancient Foe in Modern Times


Measles, a highly contagious viral disease, has been a persistent threat to human health for centuries. Vaccination rates have fallen and cases of measles are on the rise in the UK. At my hospital in the south of the UK, we have seen multiple cases over the last few weeks. The potential for serious complications in the immunocompromised in particular means we have to be vigilant to prevent further spread.

Aetiology and Transmission

Measles is caused by the measles virus, a paramyxovirus of the genus Morbillivirus. The virus is exclusively human and is transmitted via respiratory droplets when an infected person coughs or sneezes. Measles is so contagious that an unvaccinated person has a 90% chance of contracting the virus if exposed. The virus can also survive on surfaces and in the air for up to two hours, further facilitating its spread. Failure to rapidly isolate patients with symptoms/signs of measles can result in potentially vulnerable patients and staff being exposed to the virus.

Symptoms and diagnosis of measles

The clinical presentation occurs in stages. Initial symptoms, known as the prodromal phase, include high fever, cough, coryza (runny nose), and conjunctivitis (red eyes). This phase is followed by the appearance of Koplik spots—small white lesions inside the mouth, which are pathognomonic for measles.

Within 3-5 days, a maculopapular rash develops, starting at the hairline and spreading downwards to cover the face, trunk, and limbs. This rash is typically accompanied by a high fever.

You should consider measles in any patient with a fever AND rash AND one of coryza (e.g. runny or blocked nose, sneezing), OR cough, OR conjunctivitis (sore, red, watery eyes).

The rash may not have developed at presentation and measles should be considered in patients with fever, coryzal symptoms and conjunctivitis. 

Measles may present in a returning traveller – ask about known or potential contact with other cases of measles in all patients in whom you suspect the diagnosis, including those where recent contact may have been as a result of measles outbreaks abroad.  The incubation period for measles from exposure to symptoms onset is usually 10-12 days, but can vary from 7-21 days.

Laboratory confirmation can be achieved through serological testing for measles-specific IgM antibodies or reverse transcription-polymerase chain reaction (RT-PCR) testing of respiratory specimens.

What should I do if I suspect measles?

This is our local guidance from University Hospital Southampton, but check with your local virology/microbiology department for what is recommended in your hospital

‘I’         ISOLATE the patient in a side room as an urgent priority.

‘P’        PPE – wear appropriate PPE : fit tested FFP3 maskfull face visor or goggles, gloves and disposable apron (or gown for AGPs or extensive splashing anticipated).

‘C’        CALL an Infection specialist without delay. 

If you suspect measles, you must request that the patient is isolated as a matter of urgency and the above PPE must be worn by all staff entering the patient’s room. Staff who are severely immunocompromised or who are pregnant should not enter the side room of patients with suspected measles. The Infection specialist will advise on appropriate diagnostic tests including PCR for measles via a green (viral) throat or nose/throat swab. Isolation and PPE precautions should remain in place until advised otherwise by the infection prevention team.


Measles can lead to severe complications, especially in young children, pregnant women, and immunocompromised individuals. Common complications include otitis media (middle ear infection), diarrhea, and pneumonia—the latter being the leading cause of measles-related mortality.

More severe, though rarer, complications include encephalitis (inflammation of the brain), which can cause seizures, deafness, or intellectual disability. Subacute sclerosing panencephalitis (SSPE) is a fatal degenerative disease of the central nervous system that can occur years after the initial measles infection.


Vaccination is the cornerstone of prevention. The measles-mumps-rubella (MMR) vaccine is highly effective, providing immunity in approximately 97% of individuals after two doses. The World Health Organization (WHO) recommends that all children receive two doses of the MMR vaccine, the first at 12-15 months and the second at 4-6 years of age. Sadly, due to a much-publicised, and fraudulent work in the 1990s and some ongoing vaccine scepticism post-COVID, vaccination rates have declined substantially.


A once almost forgotten disease is on the rise and due to its highly infectious nature, we have to be alert to prevent further infection for vulnerable patients and colleagues. If you see a patient with any of the symptoms or signs ‘Think Measles’

UK Health Security Agency
Think measles!
Vaccination rates have fallen, and cases of measles are increasing in England. Any patient with fever and a rash is potentially infectious
Isolate anyone presenting with a rash and fever straight away
and should be directed to a side room on arrival.
• measles starts with a 2 to 4 day "prodromal" phase before the rash appears, with coryza, cough, conjunctivitis and a fever
• fever typically increases, to peak around rash onset
• rash generally starts behind the ears, spreads to the face and then expands onto the trunk and can become generalised. The rash is red, blotchy, maculopapular (not itchy) and lasts around 3 to 7 days
the rash is more difficult to spot on dark skin (see images 3, 4 and 5)
- Koplik spots may appear around the time of the rash and last for 2 to 3 days so can easily be missed. They are small white or bluish/white lesions on the buccal mucosa. They can be confused with other lesions in the mouth and so their suspected presence is an unreliable marker of measles
- the infectious period spans 8 days i.e. cases are infectious from 4 days before rash onset and for 4 full days after
- several other common rash illnesses have similar presentations (especially in young children)
e.g. roseola, parvovirus infection and scarlet fever, and so identification on clinical features alone may be unreliable
If you suspect measles call your local UKHSA Health Protection Team (HPT) to notify and conduct a risk assessment
if the patient is calling, advise them to seek medical advice from their GP over the phone or NHS 111, if this is appropriate
• if an in-person review is needed, reception staff should be alerted. The patient should be directed to a side room on arrival
report to local HPT urgently by phone to facilitate prompt risk assessment and public health action for vulnerable contacts (under 1 year olds, pregnant, immunocompromised). HPT contact details can be found here
•check for epidemiological factors that increase likelihood of measles:
- unimmunised status
- recent exposure to someone with rash/illness - recent travel
- occupation e.g. healthcare worker, nursery worker
• exclude from nursery/educational setting/ work until full 4 days after onset of rash
For patients:
Check all your staff
are fully vaccinated
⚫ routinely check vaccination history of patients
• offer vaccine if not fully protected
- children should receive
2 doses of MMR, the first at
12 months of age and the second at pre-school
(3 years and 4 months)
- there is no upper age limit for receiving MMR vaccines For staff:
• staff should have documented
evidence of two doses of the MMR vaccine or have positive antibody tests for measles
and rubella
[Image 1] Conjunctivitis from [Image 2] Koplik spots from [Image 3] Measles rash from [Image 4] Measles rash on dark skin from [Image 5] Measles rash on dark skin. [Image 6] Measles rash on back
Crown copyright 2023. Version 1. UK Health Security Agency Gateway Number 2023147. Product code: MEA2301EN. 20K 1P OCT 2023 (APS) To order more copies of this asset, please visit: or call 0300 123 1002.

Cite this article as: Iain Beardsell, "Measles – An Ancient Foe in Modern Times," in St.Emlyn's, May 30, 2024,

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