Background: For more than 50 years vaccination has been implicated as a potential trigger for GBS or for relapse in CIDP. It was a plausible hypothesis since vaccines are designed to stimulate the immune system and GBS and CIDP are diseases known to be associated with an overactive immune system. However, the evidence was weak, based on a few anecdotes and small case series. In fact, one study spanning 13 years and more than 30 million person-years, could find no evidence of an increased risk for GBS after vaccinations of any type, including influenza vaccination. The one exception was the 1976 US-nationwide vaccination programme against the swine flu (influenza A virus, subtype H1N1) which was associated with a marked increase in GBS cases. Parenthetically, this began my life-time fascination GBS as I had just arrived in the US to continue my neurology studies when these cases first began to appear. In 1976-1977 the rate of GBS in the US in individuals who had received this vaccine was 9.5/million individuals vaccinated compared to 0.79/million for unvaccinated individuals. No other explanation for this increase was found and since that time there has been the perception that the flu vaccine should not be given to individuals who have had GBS and, by logical extension, to those who had CIDP. But is this recommendation justified? No prior flu vaccination programme had been associated with an increase in the number of GBS cases and, despite close surveillance, no association with subsequent flu vaccination programmes has been found. Even the vaccine distributed during the return of the H1N1 swine flu strain in 2009 was not associated with any significant increase in GBS cases (8 extra GBS cases for every 10 million individuals vaccinated). This suggests that there was something in the way the 1976 vaccination was manufactured that made it different from any previous or subsequent vaccines.
This miniscule risk of GBS following flu vaccination should be contrasted with the risk of developing GBS following the flu. Several studies have shown that the risk of getting GBS following the flu-like illness is increased, in one study as much 18-fold. Admittedly, these illnesses were not proven to be influenza virus infections but they occurred coincident with flu outbreaks and the very high probability is that most were indeed the flu. Thus, the risk of getting GBS following the flu is many times greater than the risk of getting GBS following flu vaccination and yet the recommendation that GBS patients should not get the flu shot remains in place, even in now 2020.
This article will briefly review the risk of developing GBS or having a relapse of CIDP following some of the common vaccines given to adolescents and adults. It will not address childhood vaccinations since GBS and CIDP are vanishingly rare in pre-school children. Nor will it address which vaccine to get when several are available nor the politically charged issue of whether the vaccines discussed are necessary; just whether there is an increased risk of GBS or of CIDP relapse. As always, the decisions around getting vaccinated should be made with your own doctor who knows you and your health the best.
See answers to common questions below.
If you want to ask any further questions or anything specific to your condition and circumstances, our Medical Advisory Board are happy to help.
As already noted, other than the 1976 H1N1 vaccine, no flu vaccines have been associated with an increased risk of GBS and the risk of getting GBS following influenza infection is many times higher. Therefore, all GBS/CIDP individuals can safely get the annual flu shot with the exceptions noted below. In this year of the COVID-19 pandemic it is doubly important to get the flu shot. It will not protect against COVID-19 but it will reduce the risk of getting flu at the same time which would almost certainly lead to a more serious COVID-19 illness. Also, for those individuals over 65 year of age, smokers and those with significant concomitant illnesses, particularly lung diseases, the benefit of the flu vaccine far outweighs any tiny risk. Those who should probably not get the flu shot are:
- Individuals whose GBS occurred within 6 weeks of receiving a previous flu shot; i.e., those in whom it is reasonable and probably safer to assume that their GBS was triggered by the vaccination.
- Individuals within the first 12 months following their episode of GBS regardless of the original triggering event. This is controversial and the reason for the recommendation is unclear but it does reflect a majority view.
Meningitis vaccinations: There are many different micro-organisms that can cause meningitis but the one for which vaccination is recommended is Neisseria meningitidis (“meningococcus”). Meningococcal meningitis most often strikes young people 15-25 years of age, often those residing in group living conditions such as university dormitories and, in this context, can occur in mini-epidemics. Because it is caused by a bacterium rather than a virus it is treatable with antibiotics but can be very rapidly progressive and affected individuals can become seriously ill and can even die before treatment can be given. There are several different vaccines available; your doctor will know which is the best one in a given individual. There have been occasional reports of GBS occurring after receiving one of these vaccines but several large surveillance programmes have failed to show a significant association. Therefore, all GBS/CIDP individuals can safely get the meningitis vaccine.
Shingles is caused by the chicken pox virus also known as the varicella-zoster virus. After becoming infected with the virus, almost always during childhood, it takes up permanent residence in certain nerve cells alongside the spinal cord or around the base of the brain. It generally causes no problems but can be reactivated in adult life, usually after the age of 65 and often in association with another illness, and can cause what we know as shingles or herpes zoster. Shingles can be extremely painful and vaccination can reduce the chance that it will occur. There have been occasional reports of GBS occurring after receiving the shingles vaccine but several large surveillance programmes failed to show a significant association.
Bacterial infection with Streptococcus pneumoniae can cause pneumonia, septicaemia (blood infection) and meningitis in older patients (over 65 years) and those who are immunocompromised such as CIDP patients on steroids and some other treatments. Vaccination is recommended every 5 years for such individuals but the vaccine is not funded. A few cases of GBS have been reported following this vaccination but it is extremely rare. There are no reports of large-scale surveillance programmes but the risk must be extremely low. Therefore, it is probably safe for GBS/CIDP individuals to get the pneumonia vaccine.
The human papilloma virus is the main cause of cervical cancer and is also linked to genital cancers in men. The infection can be prevented with vaccination. Rare cases of GBS have been reported following the vaccination. A large study conducted from 2006-2008 in the US identified 36 cases of GBS following the HPV vaccination, 27 of which occurred within 6 weeks of receiving the vaccine. This does not represent an increased risk of GBS compared to non-vaccinated individuals but the study concluded the issue needs more study. Therefore it is probably safe for GBS/CIDP individuals to get the HPV vaccine but they should be made aware of the remote possibility of the vaccine triggering disease. The risk of GBS is probably outweighed by the benefit of the vaccine.
This is a mixed vaccine that protects against diphtheria, tetanus and pertussis (whooping cough). It is usually given only to children but the Centers for Disease Control in the US recommends that adults are vaccinated in certain circumstances. There have been several cases of GBS following DTAP and in the 1990’s the Institute of Medicine in the US concluded that there probably was a causal association, at least to the tetanus component. This conclusion was, however, based on a single case of a man who developed multiple episodes of a GBS-like illness after receiving tetanus toxoid. He had also had similar episodes following flu-like illnesses. A subsequent vast study in 1997 was unable to find any such association. There are also reports of tetanus toxoid triggering relapse in CIDP. It is probably safe for GBS/CIDP individuals to get the DTAP vaccine or tetanus toxoid but they should be made aware of the remote possibility of the vaccine triggering disease. The risk of GBS or of CIDP relapse should be weighed against the risk of getting a highly lethal disease (tetanus) if the context is appropriate.
Developing areas of the world are still rife with communicable diseases, many of which are serious, even fatal. These include hepatitis, yellow fever, typhoid, rabies and many others. Travelers to endemic areas are usually recommended to get vaccinated against these infections. There is insufficient data on which to base an estimate of risk for GBS/CIDP patients. However, the paucity of reported cases of GBS following these vaccines suggests that the risk is very low. Furthermore, the risks of the diseases themselves is so high that vaccination is recommended for all individuals, including those who have had GBS or have CIDP, who have the potential for exposure. One exception is the rabies vaccine derived from nerve tissue which is cheaper and therefore used in many developing countries. However, rabies is invariably fatal whereas GBS usually recovers so if the context is appropriate (e.g., being bitten by a stray dog or a bat in an area where rabies is endemic) the vaccine should still be given despite the small risk of developing GBS.
Patients with CIDP and related immune-mediated chronic neuropathies present special challenges:
- For patients whose CIDP is in remission on no current treatment the recommendations are the same as for those who have had GBS; i.e., there is little if any evidence that vaccines can trigger a return of the disease and the benefit of the vaccines in almost all instances outweighs any risk.
- Patients with active CIDP who are being treated with intravenous or subcutaneous immunoglobulin or therapeutic plasma exchange have no increased risk from vaccinations and can be vaccinated safely and effectively. Nor are they at increased risk of contracting COVID-19 infection or getting severe complications.
- Patients with active CIDP who are being treated with steroids (prednisone, methylprednisolone, etc) and those being treated with any of the other immunosuppressive drugs sometimes used in CIDP (azathioprine [Imuran], cyclophosphamide [Cytoxan], rituximab [Rituxan], and others) have an increased susceptibility to infectious diseases. Vaccination plays a critical role in preventing these infections. Before any of these treatments are started a review of the vaccination status should be done and any missing vaccinations should be updated. Once treatment has been started vaccination can still be given but may be incompletely effective. Annual flu vaccination is recommended for these patients.