Acute flaccid paralysis syndrome
Information on the reporting, investigation and management of acute flaccid paralysis (AFP) and acute flaccid myelitis (AFM).
Acute flaccid paralysis (AFP) is a rare but serious neurological illness which is normally due to inflammation of the spinal cord, known as acute flaccid myelitis (AFM).
Acute flaccid paralysis or myelitis is characterised by rapid onset of weakness of an individual’s extremities, often including weakness of the muscles of respiration and swallowing, progressing to maximum severity within 10 days. The term ‘flaccid’ indicates weakness accompanied by hyporeflexia or areflexia in the affected limb or limbs.
In the past, AFP was commonly due to poliovirus infection.
The success of the vaccination programme means that polio is now very rare internationally and has been eliminated in the UK; however, AFP may be linked to other viral infections including non-polio enteroviruses.
Regulation 2(1)(b) of the Health Protection (Notification) Regulations 2010 place a duty on registered medical practitioners (RMPs) to report any suspected infections that present or could present significant harm to human health. This covers reporting of acute flaccid paralysis (AFP) and acute flaccid myelitis (AFM) not explained by a non-infectious cause. Appropriate testing of AFP or AFM cases not explained by a non-infectious cause, to exclude polio as a causative agent, is an integral component of polio surveillance. In addition, under Schedule 1 of the Health Protection (Notification) Regulations 2010, suspected cases of acute poliomyelitis are notifiable.
To report a case, please contact the local health protection team (HPT).
Incidents
2022 polio incident
The UK Health Security Agency (UKHSA) in collaboration with the World Health Organization (WHO) Global Specialised Polio Laboratory of the Medicines and Healthcare Regulatory Agency (MHRA) conducts routine environmental surveillance for poliovirus. In 2022, UKHSA announced that this surveillance had detected Vaccine-like Poliovirus Type 2 (February to April 2022) and then Vaccine Derived Polio Virus Type 2 (VDPV2) (May to November 2022) in sewage samples collected from the London Beckton Sewage Treatment Works. A UKHSA national enhanced incident response was established, and environmental surveillance was expanded to cover a range of sites around England. The VDPV2 was only detected in sewage samples and no associated cases of paralysis were ever reported in the UK. The last detection of VDPV2 linked to this incident was in sewage collected in London in November 2022. The WHO removed the United Kingdom from the list of polio ‘infected’ countries in December 2023 after there had been no linked VDPV2 detections for a period of 12 months.
An increase in reports of acute flaccid paralysis (AFP) in the United Kingdom in 2018 and 2019
During 2018, the United Kingdom has experienced an increase in reports of cases of AFP. As at 24 September 2019, 57 cases had been identified since 1 January 2018 with a peak in October 2018. The increase was temporally associated with an upsurge in enterovirus (EV) D68 activity. A national task force has been established and investigations are ongoing (Eurosurveillance volume 24, issue 6, published 7 February 2019).
Data
Current enterovirus strains detected in the Virus Reference Department in Colindale.
Guidance for healthcare professionals
Information for parents and patients
Updates to this page
Published 19 December 2018Last updated 28 January 2025 + show all updates
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Added '2022 polio incident' section.
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Updated information on acute flaccid paralysis and acute flaccid myelitis.
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Updated the number of AFP reports received in 2018 and 2019.
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Updated the number of AFP reports received in 2018 and 2019.
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Added 'Protocol for the case note review of reported AFP cases' document.
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Updated number of AFP reports in 2018 and 2019.
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Added latest data and link to Eurosurveillance Vol 24 Issue 6.
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First published.