Guidance

Polio immunisation response in London 2022 to 2023: information for healthcare practitioners

Updated 24 May 2023

Applies to England

Background

Summary of incident – findings and interpretation

The National Institute for Biological Standards and Control (NIBSC) of the Medicines and Healthcare products Regulatory Agency (MHRA) conduct routine environmental surveillance for wild type and vaccine-like polio viruses as part of the UK’s commitment to the WHO global polio eradication programme. Vaccine-like type-2 poliovirus (PV2) isolates were found in sewage samples collected from the London Beckton sewage treatment works in February 2022 and unusually persisted for several months. This was unusual and analysis showed that all PV2 isolates identified were genetically related to each other.

The Beckton sewage treatment plant covers a large catchment area with a population close to 4 million across north-east and north-central London. The virus continued to evolve and towards the end of May 2022 met the criteria of a vaccine-derived poliovirus (VDPV2) which meant that it re-acquired the mutations that cause paralysis. VDPVs behave more like wild type virus, can sustain outbreaks and on rare occasions lead to paralytic presentations in unvaccinated individuals.

It is considered most likely that an individual entered the UK in February 2022 from a country where oral polio vaccine (OPV) has been used for supplementary immunisation campaigns and outbreak response. Recently vaccinated individuals shed the OPV virus in their stool for a few weeks after and this can be detected through the sewage surveillance. The UK switched from using OPV to Inactivated Polio Vaccine (IPV) in 2004, the year after poliovirus was declared eradicated in the WHO European region. Evidence suggests that in 2022 the virus continued to spread in some communities in North East and North Central London.

UKHSA led the investigation and response to this incident, keeping close contact with the World Health Organization (WHO) and in August 2022 it was formally confirmed that the UK had a ‘circulating’ VDPV2 based on the detection of the same isolate for more than 60 days. Evidence also suggested that the virus detected in London is genetically linked to the poliovirus detected in Israel and the US.

Ongoing sewage surveillance in London showed that no further vaccine-derived poliovirus type 2 (VDPV2) isolates have been detected since early November 2022, which suggests transmission in London has significantly reduced. The WHO requires evidence of 12 months of zero detections before the UK is no longer considered to be a polio ‘infected’ country.

Routine polio vaccine programme and coverage

Individuals born in the UK before 2004 will have been eligible for vaccination with OPV. This vaccine provides good protection against polio and also provides high levels of gut immunity. Individuals born after 2004 in the UK will have received IPV which provides excellent protection from severe polio but individuals can still become infected and spread polio virus without exhibiting any symptoms. Currently, hexavalent DTaP/IPV/Hib/HepB vaccine is offered routinely to babies at 8, 12 and 16 weeks of age. Further doses of polio-containing vaccines are given at the age of 3 years and 4 months as part of the pre-school booster (dTaP/IPV) and at around 14 years old (Td/IPV) as part of the teenage booster.

Vaccination coverage for the 3-dose primary schedule in 1-year olds in London is well below that achieved for the UK on average and uptake of the pre-school booster in 5 year olds is even lower. This falls below the WHO target of 95% coverage. Latest coverage data for the UK childhood immunisation programme is available on GOV.UK. The high-density population in the areas affected and the number of individuals under-vaccinated in those boroughs suggests that there is significant potential for the VDPV2 to continue to spread. Under-vaccinated children can become infected and pass the infection on to others. There is significant overlap between the local authorities with the lowest vaccine coverage and where VDPV2 has been detected (UKHSA COVER data 2021 to 2022).

Response to date

UKHSA declared a national enhanced incident response to coordinate the investigation and response to the polio incident. National polio guidelines outline the public health considerations when a VDPV2 is detected in environmental samples.

The NHS has strengthened ongoing work to improve uptake nationally in the routine childhood programme. In London, active call-recall of unvaccinated and partially vaccinated children under the age of 5 started in June 2022 through primary care.

The Joint Committee on Vaccination and Immunisation (JCVI) met on 25 July 2022 to review the evidence and re-iterated that the most immediate priority was to ensure all eligible individuals are up to date with their polio (IPV) vaccinations. In addition the JCVI advised that an urgent supplemental IPV booster campaign should be implemented for children aged 1 to 9 years old in London in order to:

• prevent cases of paralysis due to poliovirus
• interrupt transmission of VDPV2 in the community

The last detection of the PV2 in London sewage was in early November 2022 with evidence suggesting that transmission in London had significantly reduced. The IPV booster campaign in London ran until the 23 December 2022 and during this campaign more than 370,000 doses were delivered.

Following an evaluation of the first phase of the polio response in London a targeted catch-up campaign offering polio-containing vaccines and measles, mumps and rubella (MMR) vaccine to unvaccinated or partially vaccinated children was launched on 16 May 2023 and is aimed at under-vaccinated children in London aged 1 to 11 years. Younger children are being offered vaccines through their GP whilst older children will be caught up through clinics run in primary schools or the community. There is ongoing work to reaching communities with the lowest levels of vaccine uptake.

Information related to the 2022 London IPV booster campaign

Vaccines which were recommended for use in the IPV booster campaign in 2022

The IPV booster campaign in London was aimed at children aged 1 year (those who turned 1 by 31 August 2022) to less than 10 years of age and consisted of the below:

For children from 1 year of age to less than 3 years 4 months:

• with unknown or uncertain vaccine history – given a dose of hexavalent vaccine (then to complete primary course)
• unimmunised or only received 1 or 2 doses of primary immunisations – given dose of hexavalent vaccine (then to complete primary course)
• up to date with 3 primary doses – given additional dose of hexavalent vaccine (then for dTaP/IPV (PSB) minimum of 12 months later)

For children over 3 years 4 months to less than 10 years of age:

• with unknown or uncertain vaccine history - given dose of hexavalent vaccine (then to complete primary course)
• unimmunised or received 1 or 2 doses of primary immunisations – given dose of hexavalent vaccine (minimum 4 weeks after last IPV vaccine) and (then to complete primary course)
• with 3 primary doses but no dTap/IPV (PSB) – given dTap/IPV (PSB) with a minimum of 12 months after completing the primary course (then for adolescent Td/IPV)
• up to date with 3 primary doses and dTap/IPV (PSB), but dTap/IPV (PSB) more than 12 months before:
  • children 3 years 4 months up to 5 years - given an additional dTap/IPV (Boostrix-IPV)
  • children 6 years to 9 years given Td/IPV (Revaxis) (then for all these children to have adolescent Td/IPV when due)
• up to date with 3 primary doses and with dTap/IPV (PSB) less than 12 months before (there was no requirement for any additional dose at the time and these children were recommended to have adolescent Td/IPV when due)

The IPV booster campaign for London ended December 2022 and the catch-up immunisation programme became effective from Easter 2023.

Archived versions of the original documents, no longer in use and including the algorithm, are available to view.

London polio catch-up campaign 2023

The polio catch-up campaign launched on 16 May 2023 and is aimed at under-vaccinated children in London aged 1 to 11 years:

• children 1 to 4 years of age via primary care
• children 5 to 11 years of age through primary schools.

Any child who is not up to date with their polio or other routine childhood vaccines including MMR should be caught up in accordance with the standard algorithm as appropriate for their age.

Polio

Poliomyelitis is an acute illness that follows invasion through the gastrointestinal tract by one of the 3 serotypes of polio virus (serotypes 1, 2 and 3). The virus replicates in the gut and has a high affinity for nervous tissue.

The infection is most frequently clinically inapparent, or symptoms may range in severity from a fever to aseptic meningitis or paralysis. Headache, gastrointestinal disturbance, malaise and stiffness of the neck and back, with or without paralysis, may occur.

In a small number of cases, between 1 in 100 to 1 in 1,000 infections, the polio virus attacks the nerves in the spine and base of the brain. This can cause paralysis, usually in the legs, that develops over hours or days. If the breathing muscles are affected, it can be life threatening.

Transmission is through contact with the faeces or pharyngeal secretions of an infected person.

Please see the The Green Book polio chapter 26 for further information.

Decades ago, before the introduction of the polio vaccination programme, around 8,000 people would develop paralysis due to polio every year in the UK.

Live OPV is used in some countries around the world, particularly to respond to polio outbreaks. This vaccine generates gut immunity and for several weeks after vaccination people can shed the vaccine-virus in their faeces.

The UK switched from using OPV to IPV (which contains inactivated (killed) virus) in 2004, the year after poliovirus was declared eradicated in the WHO European region.

The Green Book

The individual Green Book chapters provide further detail on immunisations including history, the routine immunisation programme, vaccine administration and storage.

The Green Book polio chapter 26 provides further details on polio and the routine vaccination schedule.

The routine polio vaccination programme

Table 1 The routine programme for polio containing vaccine

Age	Vaccine
8, 12 and 16 weeks of age	DTaP/IPV/Hib/HepB (Infanrix hexa or Vaxelis)
3 years 4 months	dTaP/IPV (Boostrix-IPV or Repevax)
14 years	Td/IPV (Revaxis)

Vaccine composition and excipients for IPV-containing vaccine

All the IPV-containing vaccines have the same polio content and contain ingredients for virus types 1, 2 and 3.

Full details of the individual vaccines and their excipients can be found in each vaccine’s summary of product characteristics (SPC):

• Infanrix hexa (GSK)
• Vaxelis (Sanofi)
• Boostrix-IPV (GSK)
• Revaxis (Sanofi)

The routine MMR vaccination programme

Table 2 The routine programme for live MMR vaccine

Age	Vaccine
One year old (on or after the child’s first birthday)	MMRvaxPro (MSD) or Priorix (GSK)
3 years 4 months old or soon after	MMRvaxPro (MSD) or Priorix (GSK)

Vaccine excipients for MMR vaccine

Full details of the individual vaccines and their excipients can be found in each vaccine’s SPC:

• MMRvaxPro (MSD); contains neomycin – does contain gelatine
• Priorix (GSK); contains trace amount of neomycin – does not contain gelatine

Further details on porcine gelatine below, and for those who wish to take MMR vaccine that does not contain gelatine see ‘Vaccine ordering and supply’.

Porcine gelatine

The injected polio vaccines used in the UK do not contain porcine gelatine or other porcine products in the final vaccine. Animal products may be used in the manufacturing process and any that are present in the final vaccine are listed on the product insert.

There are 2 MMR vaccines, one of which contains gelatine (as above).

Gelatine is commonly used in a range of pharmaceutical products, including many capsules and some vaccines. The gelatine used in live vaccines is highly purified, derived from pigs and is used as a stabiliser.

An information leaflet on the Use of human and animal products in vaccines is available to download.

Vaccine ordering and supply

Centrally purchased vaccines for the NHS national immunisation programme and for the management of outbreaks should be ordered via ImmForm.

For additional vaccine supply and to order larger quantities of vaccines or to order a quantity of MMR vaccine that does not contain porcine gelatine contact ImmForm directly.

ImmForm contact details are available in the how to register: ImmForm helpsheet.

Up to date information on vaccine availability can be found in the latest edition of Vaccine update, the newsletter for healthcare practitioners outlining vaccination policies and procedures.

Storage of vaccines

All vaccines used in the routine immunisation programme should be stored in a pharmaceutical vaccine refrigerator within the recommended +2C to +8C temperature range. Vaccines should be stored in the original packaging. Further detail available in the Green Book chapter 3.

In the event of an inadvertent or unavoidable deviation of these conditions, vaccine that has been stored outside the recommended +2C to +8C temperature range should be quarantined and risk assessed for suitability of continued ‘off-label’ use or appropriate disposal. Refer to vaccine incident guidance: responding to errors in vaccine storage, handling and administration for further information.

Legal mechanisms available to administer the vaccines

All vaccines are classified as prescription only medicines (POMs). This means that they are subject to legal restrictions and there needs to be an appropriate legal framework in place before they can be supplied and or administered. Any person who supplies and administers a vaccine must have a legal authority to do so. This legal authority may be in the form of a written patient specific prescription, a Patient Specific Direction (PSD) or a Patient Group Direction (PGD).

UKHSA develop and publish PGD templates for all vaccines used in the routine immunisation programme.

UKHSA national template PGDs must be organisationally authorised in section 2 before being adopted by provider organisations and section 7 also completed.

Vaccine administration queries

Child with uncertain vaccine history or without any reliable immunisation records

Every effort should be made to establish documented or reliable vaccine history for each child. However, if no vaccine records are available then the recommendation would be to treat the child as unimmunised and offer a full course of immunisations following The routine immunisation schedule and the algorithm for Vaccination of individuals with uncertain or incomplete immunisation status. Individuals coming to the UK part way through their immunisation schedule should be transferred onto the UK schedule and immunised as appropriate for their age. If the primary course has been started but not completed, then the course should be resumed and there is no need to repeat doses or to restart the course.

Child given the ‘incorrect’ vaccine recommended for their age

If Td/IPV (Revaxis) has been given in error instead of dTaP/IPV (Boostrix IPV) to a child who has not received their pre-school booster, then an additional dTaP/IPV (Boostrix IPV) vaccine would be required after an interval of 4 weeks to ensure the child is protected against pertussis. This will then also allow for the dose to be counted as a pre-school booster for coverage estimates and GP payments.

For children who received an additional dose of vaccine as part of the London IPV-booster campaign

Children between the ages of 1 year and 3 years 3 months who received an additional dose of IPV-containing vaccine as part of the London IPV-booster campaign should be offered dTaP/IPV, the pre-school booster (PSB), when it is due at 3 years 4 months of age, ideally leaving a minimum 12-month interval after the IPV-booster. If the 12-month interval is disregarded in error there is no need to repeat the dose, however the recommendation is to wait 12 months after the additional dose to optimize the benefit of boosting.

Children of 3 years 4 months of age or older who were given an additional dose of IPV-containing vaccine over 3 years and 4 months of age, and who have received a full course of primary immunisations, no further dose of dTaP/IPV is needed as the child will have continued protection until the time of the teenage booster Td/IPV (Green Book Chapter 11). If the additional dose of vaccine was given between 3 years and 3 years 4 months of age there would be no reason to repeat the dTaP/IPV (PSB), but the recommendation is not to give this vaccine routinely before 3 years 4 months.

Timing of the adolescent booster following additional dose of IPV-containing vaccine

Children in date with their routine primary immunisations and given an additional IPV-containing vaccine as part of the IPV booster campaign in London should be offered Td/IPV vaccine according to the routine immunisation schedule at 14 years of age (school Year 9), regardless of the interval from the additional dose of vaccine. For the majority of children this will be an interval of at least 5 years.

Giving more than one vaccine at the same time

Where 2 or more injections are recommended at the same time these should ideally be given in different limbs. Where this is not possible, injections in the same limb should be given at least 2.5cm apart.

IPV-containing vaccines can be co-administered with other vaccines including MMR and flu.

Giving 2 Hib-containing vaccines at the same time

If a child over one year of age is being caught up with their routine immunisations and requires 2 Hib-containing vaccines such as the combined Hib/MenC vaccine and hexavalent vaccine, then 2 Hib-containing vaccines can be given at the same time.

Baby born to a hepatitis B infected mother

If a child is being followed up on the neonatal selective Hepatitis B programme (as born to a hepatitis B infected mother), and they require a dose of hexavalent vaccine at the same time as the scheduled dose of monovalent vaccine as part of the pathway, then the hepatitis B content of the hexavalent vaccine would count as the dose of hepatitis B vaccine and no additional monovalent vaccine would be required for this dose. The child should then continue with the hepatitis B schedule as part of the pathway.

See the Hepatitis B: antenatal screening and selective neonatal immunisation pathway for further information on the pathway.

Routine immunisations and the possibility of side effects

Parents should be informed that there may be some short-lasting redness, swelling or tenderness in the limb around the injection site. Some children may develop a mild temperature or irritability, this should only last for a day or two.

Following MMR vaccine there may be malaise, fever and possibly a rash may develop usually about a week after immunisation and lasts about 2 to 3 days.

For further information see the individual vaccine SPC for details.

Reporting side effects

As with all vaccines and other medicines, healthcare practitioners and patients are encouraged to report suspected adverse reactions using the Yellow Card reporting site.

Children who have received oral polio vaccine (OPV) in another country

The trivalent OPV was withdrawn in April 2016 and replaced with the bivalent oral poliovirus vaccine (bOPV), which contains only attenuated virus of types 1 and 3. This is to reduce the risk of tOPV seeding new type 2 circulating vaccine-derived polioviruses (cVDPV2). bOPV does not give immunity against serotype 2 and even though wild type 2 virus has been eradicated since 1999, protection against cVDPV2 is required.

Monovalent OPVs for type 1 (mOPV1), and type 3 (mOPV3) poliovirus are also available for use in outbreak response in some countries. Stockpiles of monovalent OPV type 2 (mOPV2) and novel OPV type 2 vaccines are also held by WHO and can be deployed in response to circulating Vaccine Derived Polio Vaccine type 2 outbreaks if appropriate. Monovalent vaccines only provide protection against the serotype contained in the vaccine so, for example, mOPV2 will not provide immunity against serotypes 1 and 3.

If a child has received any oral polio vaccine (OPV) in another country since 2016 as part of their primary course or pre-school booster, these doses should be discounted. Most countries have a mixed OPV and IPV schedule and so if sufficient IPV doses have been received for their age, then no additional IPV doses are needed.

Children who have received IPV for their primary and/or pre-school doses and then received a dose of OPV as part of a one-off polio immunisation campaign do not require a dose of IPV to replace this additional OPV dose.

Older siblings attending clinic at the same time as a younger member of the family

Children over 11 years of age are not part of the targeted catch-up programme but if older children present in clinic this is an opportunity to check their vaccination status and advise on how they can be brought up to date if they have missed out on any of their vaccinations.

Child has moved to live outside London permanently

If a child has received a letter of invitation for catch-up vaccinations but they have moved to live outside London permanently, their immunisation records should be checked, and the child brought up to date with any outstanding routine immunisations in the usual way.

The next steps

The impact of the London IPV booster and the catch-up campaign will be evaluated through monitoring of vaccine coverage, including inequalities.

UKHSA will continue to closely monitor emerging evidence around the polio incident and the control measures deployed. JCVI will issue further advice on additional interventions if required.

Resources

Polio: national guidelines

JCVI statement on a vaccination strategy for the ongoing polio incident, published 10 August 2022

Polio vaccine catch-up campaign for London as sewage surveillance findings suggest reduced transmission, 23 March 2023.

Young people at risk of disease as concerning numbers miss out on life-saving vaccines), 24 April 2023.

Poliovirus detected in sewage from North and East London, 22 June 2022.

Polio: detection of VDPV2 in London sewage samples, 22 June 2022.

The complete routine immunisation schedule

Vaccination of individuals with uncertain or incomplete immunisation status

Oxford vaccine group

Use of human and animal products in vaccines

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