Dialysis patients do respond to the RSV vaccine, six weeks later than everyone else

Design

observational immunogenicity study with age- and sex-matched controls, sampling at baseline and weeks 2, 5, 8, 16 and 32

Population

20 patients receiving haemodialysis (median age 78.4 years, 55% female, median dialysis duration 23 months) and 15 matched controls with normal kidney function

Primary outcome

RSV-specific IgG by ELISA and cellular responses by multiparameter flow cytometry after a single dose of Arexvy

Effect

IgG stable to week 5, rising at week 8 (16.8 SU), peaking at week 16 (17.5 SU) from a median 12.6 SU baseline and 14.6 SU at week 32; controls rose by week 2; titres correlated negatively with dialysis duration

Patients on haemodialysis are among the most vulnerable to respiratory syncytial virus, being older, immune-impaired and repeatedly exposed in healthcare settings, and immunogenicity data in this group have been absent. This observational study gave a single dose of the RSV vaccine Arexvy to 20 haemodialysis patients, median age 78.4 years, median dialysis duration 23 months, and followed antibody and cellular responses at weeks 2, 5, 8, 16 and 32 against 15 age- and sex-matched controls with normal kidney function.

The response arrived, but late. RSV-specific IgG was unchanged through week five, rose significantly at week eight, peaked at week 16 and was still above baseline at week 32. Matched controls were already rising at two weeks. Cellular responses were intact and earlier: RSV-specific CD4 T cells increased at week two, mostly producing interferon-gamma, interleukin-2 or tumour necrosis factor, and plasmablasts expanded at weeks five to eight.

The finding that should change practice is the relationship with dialysis vintage. Antibody levels correlated negatively with time on dialysis, and patients dialysing for under a year had significantly higher titres. That argues for vaccinating early in the dialysis career rather than deferring, and ideally before dialysis starts, in advanced chronic kidney disease clinic.

The practical consequence of the delay is timing. If protection takes eight to sixteen weeks rather than two, vaccinating at the start of the RSV season is too late. Give it well ahead of the season, and do not interpret an early antibody test as failure. Read the size honestly: 20 patients, immunological endpoints and no clinical outcomes, so this shows the vaccine works immunologically in dialysis patients, not by how much it prevents disease.

• Vaccinate against RSV well before the season starts; protection took 8 to 16 weeks in these patients
• Offer RSV vaccination in advanced CKD clinic rather than waiting until the patient is established on dialysis
• Prioritise patients newly on dialysis, who mounted significantly higher antibody titres
• Do not check antibodies at two to five weeks and conclude the vaccine failed
• Note that these are immunological endpoints in 20 patients; no clinical protection was measured

The statistics, in plain English

With 20 patients and 15 controls this is a small immunological study, so the timing difference, which is large and consistent across successive samples, is more reliable than any single titre comparison. Antibody titres are a surrogate: no threshold has been established that guarantees protection against RSV, so a rise from 12.6 to 17.5 standard units tells you the immune system responded, not how well the patient is protected. The negative correlation with dialysis duration comes from within these 20 patients, so it is a signal worth acting on given the low cost of vaccinating earlier, not an established dose-response relationship.

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.