Table 1.

Current and emerging COVID-19 vaccines and their relevance to MS.

COVID-19 vaccine	mRNA vaccines (Moderna, Pfizer)	Inactivated (Sinopharm), protein-based (Novavax), and DNA (Inovio) vaccines	Human viral vector vaccine (Johnson & Johnson)	Simian viral vector vaccine (AstraZeneca)	Live-attenuated vaccine (Meissa)
Number of doses	Two	Two	One	Two	One
Severe immune-mediated adverse events	Rare facial palsy	None reported	One report of MS relapse in an untreated patient	One report of vaccine-related TM and one report of MS relapse in an untreated patient	Unknown, but has a higher potential for immune-mediated adverse events and a higher risk of causing COVID-19 infection in immunocompromised patients
IFN-B, GA, teriflunomide, and natalizumab	No major safety or efficacy concerns	No major safety or efficacy concerns	No major safety or efficacy concerns	No major safety or efficacy concerns	Not preferred
Fumarates	Possible decreased vaccine efficacy in patients with severe lymphopenia Consider dose interruption in severely lymphopenic patients to allow for lymphocytic recovery prior to vaccination	Possible decreased vaccine efficacy in patients with severe lymphopenia Consider dose interruption in severely lymphopenic patients to allow for lymphocytic recovery prior to vaccination	Possible decreased vaccine efficacy in patients with severe lymphopenia Consider dose interruption in severely lymphopenic patients to allow for lymphocytic recovery prior to vaccination	Possible decreased vaccine efficacy in patients with severe lymphopenia Consider dose interruption in severely lymphopenic patients to allow for lymphocytic recovery prior to vaccination	Not preferred and may be especially dangerous in patients with severe lymphopenia
S1P modulators	Possible decreased cellular vaccine response Interruption of treatment not recommended to avoid MS rebound	Possible decreased cellular vaccine response Interruption of treatment not recommended to avoid MS rebound	Possible decreased cellular vaccine response Interruption of treatment not recommended to avoid MS rebound	Possible decreased cellular vaccine response Interruption of treatment not recommended to avoid MS rebound	Contraindicated
Ocrelizumab	Possible decreased humoral > cellular vaccine response Consider vaccination between month 3 and 5 of the treatment cycle to maximize vaccine efficacy Consider delaying infusion to one month after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination between month 3 and 5 of the treatment cycle to maximize vaccine efficacy Consider delaying infusion to one month after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination between month 3 and 5 of the treatment cycle to maximize vaccine efficacy Consider delaying infusion to one month after vaccination	Possible decreased humoral > cellular vaccine response Consider vaccination between month 3 and 5 of the treatment cycle to maximize vaccine efficacy Consider delaying infusion to one month after 2nd vaccine	Contraindicated
Ofatumumab	Possible decreased humoral > cellular vaccine response Consider vaccination one month after injection and delay next injection for one month after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination one month after injection and delay next injection for one month after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination one month after injection and delay next injection for one month after vaccination	Possible decreased humoral > cellular vaccine response Consider vaccination one month after injection and delay next injection for one month after 2nd vaccine	Contraindicated
Rituximab	Possible decreased humoral > cellular vaccine response Consider vaccination 3 to 6 months after injection and delay next injection for 4–6 weeks after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination 3 to 6 months after injection and delay next injection for 4–6 weeks after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination 3 to 6 months after injection and delay next injection for 4–6 weeks after vaccination	Possible decreased humoral > cellular vaccine response Consider vaccination 3 to 6 months after injection and delay next injection for 4–6 weeks after 2nd vaccine	Contraindicated
Alemtuzumab	Possible decreased cellular > humoral vaccine response Consider vaccination six months after completion of treatment course Consider delaying treatment course to one month after 2nd vaccine	Possible decreased cellular > humoral vaccine response Consider vaccination six months after completion of treatment course Consider delaying treatment course to one month after 2nd vaccine	Possible decreased cellular > humoral vaccine response Consider vaccination six months after completion of treatment course Consider delaying treatment course to one month after vaccination	Possible decreased cellular > humoral vaccine response Consider vaccination six months after completion of treatment course Consider delaying treatment course to one month after 2nd vaccine	Contraindicated
Cladribine	Possible decreased humoral > cellular vaccine response Consider vaccination six months after completion of the second treatment cycle Consider delaying treatment course to one month after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination six months after completion of the second treatment cycle Consider delaying treatment course to one month after 2nd vaccine	Possible decreased humoral > cellular vaccine response Consider vaccination six months after completion of the second treatment cycle Consider delaying treatment course to one month after vaccination	Possible decreased humoral > cellular vaccine response Consider vaccination six months after completion of the second treatment cycle Consider delaying treatment course to one month after 2nd vaccine	Contraindicated
Other considerations	Widely available vaccines and many MS patients received them without red flags	Inactivated and protein-based vaccines have a long track record of safety and compatibility with MS DMTs	Single dosing is convenient for patients on cell-depleting DMTs who wish to coordinate vaccine timing with DMT dosing to maximize vaccine efficacy	More reports of demyelinating side effects than other COVID-19 vaccines but they remain rare, isolated events	Lower risk for COVID-19 infection in untreated MS patients but possibly higher risk for inducing relapse