Toronto: Multiple studies have shown that individuals with kidney failure and undergoing dialysis mount weaker antibody responses after Covid-19 vaccination, but new research indicates that these individuals’ immune responses are still capable of protecting against SARS-CoV-2 infection and severe disease.
In the study, published in JASN, individuals who had received a single Covid vaccine dose were 41 per cent less likely to become infected with SARS-CoV-2 and 46 per cent less likely to develop severe Covid-19 that required hospitalisation or resulted in death.
Those who had received two doses were 69 per cent and 83 per cent less likely to become infected or experience severe disease, respectively.
On the other hand, the risk of hospitalisation in the unvaccinated group was 52 per cent and the mortality rate was 16 per cent, whereas the risk of hospitalisation in the 2-dose group was 30 per cent and the mortality rate was 10 per cent.
“Patients on maintenance dialysis often have suppressed immune systems and many are unable to isolate because they must attend dialysis treatments three times per week in a dialysis centre,” said Matthew Oliver, from University of Toronto in Canada.
“Reducing hospitalisations and deaths is very important in this population because approximately two-thirds of these patients were hospitalised and 1 in 4 died when infected by SARS-CoV-2 early in the pandemic,” he added.
For the study, the team analysed health records for 13,759 individuals receiving maintenance dialysis between December 21, 2020 and June 30, 2021 – 17 per cent of whom were unvaccinated and 83 per cent of whom had received at least 1 mRNA Covid-19 vaccine dose.
They found were no significant differences in vaccine effectiveness among age groups, mode of dialysis, or vaccine type (Pfizer-BioNTech or Moderna).
“Our results show that 2 doses of an mRNA vaccine significantly protected this population, preventing many hospitalisations and deaths and reducing the burdens on patients, families, and the health care system,” said Oliver.
“The effectiveness of the vaccines was less than that seen in studies in the general population but still provided substantial protection,” he noted.
It is now recommended that all adults and teenagers, especially those who are immunocompromised, receive a third dose of Covid vaccine to ensure an optimal immune response.