Table 1

Clinical exacerbations of multiple sclerosis associated with URTI and with serological rise in antibody titres

PeriodPatient-weeks (n)Attacks (n)Attack rate/y
All symptomatic URTI:1-150
 At risk430273.3
 Not at risk2086651.6
Serologically proved viral infection:1-160
 At risk6475.7
 Not at risk1552501.7

  • ↵1-150 p=0.004, odds ratio 2.0 (95% CI 1.3–3.2).

  • ↵1-160 p=0.006, odds ratio 3.4 (95% CI 1.5–7.8).

  • URTI=Upper respiratory tract infection.

  • There are less patient-weeks in the serological data as blood was only collected monthly for the first 9 months.