#MSCOVID19: transverse myelitis is not a reason to avoid being vaccinated

Barts-MS rose-tinted-odometer: ★★★

I am getting an increasing number of emails and direct messages on social media platforms about the transverse myelitis (TM) risk and COVID-19 vaccines; in particular the Oxford-AstraZeneca (Ox-AZ) vaccine. Some of the people who have contacted me have decided to forgo the vaccine and take their chances with COVID-19 and its potential sequelae. 

I want to stress that at present the link between COVID-19 vaccination and TM is very tenuous and arguably not there. Contrary to what misinformation is out there 3 cases of TM did not occur in relation to the Ox-AZ vaccine. This is the data as presented by the EMA in their ‘COVID-19 Vaccine (ChAdOx1-S [recombinant]) RISK MANAGEMENT PLAN’:

“There were 3 serious adverse events (SAEs) of demyelinating disease: 2 cases in the Ox-AZ group (1 case of transverse myelitis, and 1 case of multiple sclerosis in a participant with pre-existing, but previously unrecognised, multiple sclerosis), and 1 case of myelitis in the control group.” (EMA-ChAdOx1-S RMP)

It is important to realise that the subject with MS had signs of MS disease activity that predated vaccination, i.e. the vaccine did not cause the MS. This means that the two cases of TM were balanced between the Ox-AZ and the control arm (meningococcal vaccine).  

So the cynical anti-Vaxxers will argue that the TM is simply due to vaccination and a strong argument not to be vaccinated. So how common is TMTM post-vaccination?  

“The association between vaccines and acute demyelinating events has been assessed in a range of studies and expert reviews, including a population-based analysis of nearly 64 million vaccine doses in the US, which concluded that if there is an association between transverse myelitis and vaccines, it is < 2 per million doses of live-zoster and live-attenuated influenza vaccines, and < 1 per million doses for other vaccines (Baxter et al 2016). Moreover, demyelinating diseases occur more frequently with infections than with vaccination (Miravalle et al 2010). Taken together, the evidence is inconclusive regarding a causal relationship between contemporary vaccines and acute demyelinating events (Principi and Esposito 2020, Mouchet et al 2018, Phillips et al 2018).” (EMA-ChAdOx1-S RMP)

I suspect that TM post-COVID-19 will turn out to be commoner than TM post-COVID-19-vaccination. I have already done a blog post about the former, i.e. TM occurring in people who have had SARS-CoV-2 infection.

The annual incidence of TM ranges from 1.34 to 4.60 cases per million but increases to 24.6 cases per million if acquired demyelinating diseases like MS and neuromyelitis optica (NMO) are included. The John Hopkins COVID-19 site states that worldwide over 300M people have already received at least one dose of a COVID-19 vaccine and over 30M have received two doses as of the 8th March 2021. I think this number of COVID-19 vaccinations would be sufficient to see a TM signal. The one signal that we thought may have emerged was Bell’s palsy, but the number of cases seems to be in keeping with the background rate in the general population. Bell’s palsy was seen in the phase 3 Ox-AZ trial, but again the number of events was balanced. 

“Nonserious AEs of facial paralysis occurred in 3 participants in the Ox-Az group and 3 participants in the control group.” (EMA-ChAdOx1-S RMP)

“The MHRA continues to review cases reporting Bell’s Palsy and to analyse case reports against the number expected to occur by chance in the absence of vaccination (the ‘natural rate’). The number of reports of facial paralysis received so far is similar to the expected natural rate and does not currently suggest an increased risk following the vaccines. We will continue to monitor these events, including through the evaluation of electronic healthcare record data.” (MHRA Coronavirus vaccine – weekly summary of Yellow Card reporting, 4th March 2021)

The MHRA safety data has not shown a TM signal with either of the vaccines and that is now with millions of doses of vaccine given. 

Please remember a lot of patients with TM go onto develop MS. Thousands of people with MS have now had one of the vaccines and the last I had heard only 6 relapses had been reported to the MHRA; a very low number considering how many MS relapses occur in the UK every year. No signal has emerged in Israel either with TM or MS relapses post COVID-19 vaccination. The one caveat about Israel’s data is that it is dominated by the Pfizer-BionTech vaccine. 

As the plan is to vaccinate the whole adult population there will be people who get TM post-vaccination. This will happen by chance. Unless there are large numbers of cases of TM, as what happened with Guillain-Barre Syndrom (GBS) after the H1N1 flu vaccine, it will be very difficult to prove causation. 

Nobody is being forced to be vaccinated. If you don’t want to be vaccinated just say no, but if you decided not to be vaccinated you need to realise that you are likely at some point to get COVID-19. SARS-CoV-2 is almost certain to become an endemic viral infection, i.e. the virus won’t disappear. So you need to think about the risks that getting COVID-19 entails. In general, most people who get COVID-19 are likely to get mild to moderate disease, but there are no guarantees that you won’t get the severe disease with the potential to die. Then there is the issue of long COVID-19, which affects about 10% of people who get COVID-19. So not having the vaccine has it own risks.

My advice remains the same: #GetVaccinated ASAP; TM is not a reason to avoid the vaccines and it is not a reason to avoid the Ox-AZ vaccine either. 

CoI: multiple

Twitter: @gavinGiovannoni                                              Medium: @gavin_24211