Nora Möhn and her team (Journal of Clinical Medicine, 2020, 9:4067) made a summary of Covid-19 infection in 873 MS patients described in various medical journals. The course of the infection is known in 700 of these cases. Among them, 11% were not being treated, 36% were being treated with rituximab or Ocrevus (anti-CD20 antibodies), 12 % with Copaxone or interferons, 11 % with Gilenya, 9 % with Tysabri, 8 % with Tecfidera, 7 % with Aubagio, 3 % with Mavenclad and 1% with Lemtrada. The great majority (71 %) of these patients were not hospitalised as they presented with a slight form of the disease, 22 % were hospitalised but did not require ventilation, 3 % required ventilation in intensive care units and 4 % died. Among the 28 patients who died, 14 were not being treated for MS, 7 were being treated with anti-CD20s and only 5 did not have an underlying condition other than MS. Age, obesity and cardiovascular problems were the best predictors of death. Overall, the number of severe cases or deaths remained fairly low in MS patients and it is likely that MS treatments protect against the more serious forms of Covid-19, especially that involving extensive lung damage.

 

Another recent study was produced by the Barcelona group (Ana Zabalza et al., European Journal of Neurology, in press) and is based on the clinical history of 93 MS patients infected with Covid. The incidence of the disease among all MS patients was estimated to be 6.3%, which is very close and not significantly different from incidence among the general population of Catalonia (6.1 %). Out of these 93 patients, 20.4 % were hospitalised, 9.7 % developed a severe form of the disease and 2.2 % died. Predisposing factors to infection with Covid did not include their ongoing treatment, but the fact of living in a large city (Barcelona), being a young adult and having been in contact with a Covid-positive person. The only factor in the severity of the disease was being aged over 60. As in the wake of any viral infection, patients may experience a MS flare-up; this was observed in 4 patients. Infected patients developed anti-Covid antibodies: 50% among treated patients and 70% among untreated patients. However, this figure was far lower in the case of patients treated with anti-CD20s (16%).

 

 

As far as anti-Covid vaccination is concerned, therefore, it cannot be said that MS patients have priority. This only applies if they are aged over 65 and in the presence of comorbidities such as excess weight, diabetes, high blood pressure and cardiovascular problems. If a MS patient requires prompt treatment with Lemtrada, Mavenclad or Ocrevus, it is undoubtedly advisable to vaccinate the patients against Covid prior to beginning the treatment and to wait for 6 weeks after they have received the second dose. Vaccination is risk-free in the case of treatment with first-line drugs (interferons, Copaxone, Aubagio, Tecfidera) or second-line treatment with Tysabri or Gilenya. If the patient has already been treated with Lemtrada or Mavenclad, the vaccine should be given after 6 months to ensure maximum vaccine efficiency. In the case of treatment with Ocrevus, it is advisable to vaccinate the patient 12 weeks after the last course of treatment and 6 weeks before the next one. No data or reports suggest that side effects are commoner in MS patients than among the general population. It should be remembered that none of the anti-Covid vaccines uses a live attenuated virus, unlike, for instance, the yellow-fever vaccine.