Guidance

Information for healthcare professionals on Guillain-Barré Syndrome (GBS) following COVID-19 vaccination

Updated 17 December 2021

What is known about the reports of GBS following COVID-19 vaccination

Guillain-Barré Syndrome (GBS) is a rare condition where the body’s immune system damages nerve cells and typically presents with sensory abnormalities, muscle weakness and autonomic dysfunction, often triggered by infection, although the cause is not always identified. It usually develops over hours or days, starting in the extremities (hands and feet) before spreading to the arms and legs, typically affecting both sides. Initial symptoms include numbness, pins and needles, muscle weakness, pain, and balance and coordination problems. Severity can range from mild, transient weakness to complete paralysis. It is generally a single episode in a patient’s life.

The incidence in the UK population is estimated at 2 per 100,000 per year and increases with age and is more common in men, with similar numbers is other western countries. In the USA, the incidence is similar and between 3,000 and 6,000 people develop GBS each year.

Since all adults in the UK have been offered a coronavirus (COVID-19) vaccine, a certain number of cases of GBS would be expected to occur co-incidentally following vaccination. Cases following COVID-19 vaccination have been reported in the UK and internationally and investigations are ongoing to establish if the rate of reported cases is above what would be expected in the population and whether there is evidence of an association with these vaccines. GBS cases have been reported following other vaccination programmes, with research particularly focusing on GBS and the seasonal flu vaccine. These studies have shown variable results and where an increase has been observed, it has been in the range of 1 to 2 additional GBS cases per million flu vaccine doses administered. However, importantly the evidence suggests that an individual is more likely to get GBS after having flu infection compared with after the vaccination.

UK reports

As of 8 December 2021, in the UK there have been 472 reports of GBS following AstraZeneca (AZ) vaccination and 27 reports of Miller Fisher syndrome, a variant of GBS which causes abnormal muscle coordination, paralysis of eye muscles and loss of tendon reflexes. There have been 69 reports of GBS and 2 of Miller Fisher syndrome following Pfizer/BioNTech vaccination and 7 reports of GBS following Moderna vaccination. Over this time period, 24.9 million first doses and 24.1 million second doses of the AZ vaccine have been administered, 24.8 million first doses and 21.2 second doses of the Pfizer/BioNTech vaccine have been administered, and 1.5 million first doses and 1.4 million second doses of the Moderna vaccine.

The observed number of cases in the UK based on cases reported to the Medicines and Healthcare products Regulatory Agency (MHRA) by the COVID-19 yellow card scheme, have been compared with the number of expected GBS cases in the immunised population. The number of cases reported following vaccination with the Pfizer/BioNTech or Moderna vaccines are lower than the number expected to occur by chance. For the AZ vaccine, GBS has very rarely been reported within 6 weeks of the first dose, with the risk approximately 5.6 extra cases of GBS per million doses. Rates after the second dose are within background levels and there is no evidence of a higher rate of reporting in individuals who have had GBS previously. See the Green Book for further information. Following a review of the most recent data for the AZ vaccine and advice from the Commission on Human Medicines and its COVID-19 Vaccines Benefit Risk Expert Working Group, the product information for the AZ vaccine has been updated to include GBS in the adverse reactions associated with the vaccine. Health professionals and the public are encouraged to look out for the signs and symptoms of GBS. The MHRA will continue to review the vaccination data; however, it is important to note that the assessment from the Expert Working group is that the benefits of vaccination continue to outweigh these rare side-effects.

International reports

In the US, as of 13 July 2021 there were 100 preliminary reports of GBS after receiving the Johnson & Johnson (Janssen) vaccine and 1 death with 12.5 million vaccine doses administered. Information on GBS has now been included on the vaccine recipient and vaccination provider factsheets. The Johnson & Johnson (Janssen) vaccine has been approved for use in the UK but has not been deployed in the UK vaccination programme. No signal in the US has been identified with either the Moderna or Pfizer/BioNTech vaccines. In Europe, the European Medicine Agency recommended the addition of a warning to raise awareness of GBS following vaccination with the AZ vaccine, with 227 GBS cases reported by 27 June 2021 and 51.4 million doses given by 20 June 2021. A similar recommendation has been made for the Johnson & Johnson (Janssen) vaccine.

The World Health Organization has also reviewed the data, noting that increased reports have not been observed following mRNA COVID-19 vaccines (Pfizer/BioNTech and Moderna vaccines), but that the potential benefits of the Johnson & Johnson (Janssen) and AZ vaccines continue to outweigh any potential risk of GBS.

Have cases been reported after the 1st or 2nd dose of COVID-19 vaccine or any specific vaccine?

The MHRA are analysing all reports of GBS following COVID-19 vaccination and this information will be shared when it becomes available. A causal link between COVID-19 vaccination and GBS has not been proven for the Pfizer/BioNTech and Moderna vaccines and cases of GBS that occur following vaccination may occur by chance, with a background rate of GBS of 2 per 100,000 per year. For the AZ vaccine, GBS has very rarely been reported within 6 weeks of the first dose, with the risk approximately 5.6 extra cases of GBS per million doses. Rates after the second dose are within background levels and there is no evidence of a higher rate of reporting in individuals who have had GBS previously. See the Green Book for further information.

For the Johnson & Johnson (Janssen) vaccine which has a 1 dose schedule, data from the US indicates that there is an increased risk of GBS in the 42 days following this single dose, and investigations are ongoing to assess whether there is a causal relationship between the vaccine and the cases of GBS.

Reporting a suspected case of GBS following COVID-19 vaccination

It is very important that all suspected cases are reported to the MHRA using the COVID-19 Yellow Card scheme.

Should someone who has had GBS unrelated to COVID-19 vaccination have their COVID-19 vaccination?

Yes, they should be vaccinated as recommended for their age and risk group, including booster doses.

A causal link between COVID-19 vaccination and GBS has not been proven and there is no evidence of a higher rate of reporting of GBS following COVID-19 vaccination in individuals who have previously had GBS. Hence, the balance of risk benefit is in favour of completing the recommended COVID-19 vaccination schedule. See the Green Book for further information.

If someone has had GBS after a COVID-19 vaccination, should they have subsequent doses?

If GBS develops in an individual after a dose of either the Pfizer/BioNTech or Moderna vaccine, they should complete the vaccination schedule with the same vaccine once fully recovered. The balance of risk benefit remains in favour of completing a full COVID-19 vaccine schedule and there is an increased rate of known side-effects if mixed schedules are used. If the next dose is a booster dose, then the Pfizer/BioNTech vaccine is recommended.

If GBS develops within 6 weeks of receiving the AZ vaccine, then on a precautionary basis Pfizer/BioNTech should be given for any subsequent doses. Please see the Green Book for further information.

Sources

COVID-19 Greenbook chapter 14a

Coronavirus vaccine - weekly summary of Yellow Card reporting

GBS (Guillain-Barré Syndrome) and Vaccines, Vaccine Safety, Centers for Disease Control and Prevention (CDC)

06 Public Safety Update, VAXZEVRIA, 14 July 2021, European Medicines Agency

Interim Clinical Considerations for Use of COVID-19 Vaccines, Centers for Disease Control and Prevention (CDC)