Patients on Dialysis Need mRNA COVID Booster Shot: UK Study

Marlene Busko

August 20, 2021

In-center hemodialysis patients — especially those without prior COVID-19 who received two doses of an adenoviral-vector vaccine — should receive a booster shot with a third dose of an mRNA-type COVID-19 vaccine as soon as possible, evidence from a new UK study suggests.

The findings are from an interim analysis of a planned study in more than 1000 patients on hemodialysis across the UK. Researchers have submitted the findings to the UK Joint Committee on Vaccination and Immunisation as evidence of how to best protect patients on hemodialysis, who are at higher-than-average risk of COVID-19.

Immunocompromised patients in the UK are expected to be prioritized to receive a third dose of COVID-19 vaccine this autumn.

Meanwhile, the US Centers for Disease Control and Prevention recently endorsed a third dose of an mRNA vaccine for immunocompromised patients, including those on dialysis, as previously reported.

The Oxford AstraZeneca vaccine is not approved for use in the United States, although a one dose adenoviral-vector vaccine from Johnson & Johnson was given emergency use authorization. But for now, people who've received the one-dose Johnson & Johnson vaccine have not been cleared to get a second dose of any COVID-19 vaccine in the UK, although the number of people thought to be affected is small.

Three Main Findings of UK Study

UK researchers examined the immune response — blood levels of neutralizing antibodies in response to SARS-CoV-2 virus variants in a laboratory test — in 178 patients on dialysis 33 days after they had received the second dose of a Pfizer/BioNTech mRNA vaccine or Oxford AstraZeneca adenoviral-vector vaccine.

There were three main findings.

First, in the 108 patients on dialysis without prior COVID-19, the antibody response to the highly infectious Delta variant of the virus was sixfold lower in patients who had received two doses of the AstraZeneca versus the Pfizer/BioNTech vaccine.

Similarly, responses to the Alpha and Beta variants were fourfold and threefold lower, respectively, after two doses of the AstraZeneca versus the Pfizer/BioNTech vaccines.

Second, patients on hemodialysis without prior COVID-19 who received two doses of mRNA vaccines had similar neutralizing antibody responses as similar healthy control patients.   

Third, among 70 patients on hemodialysis who had prior COVID-19, patients who received either vaccine had detectable neutralizing antibodies, showing that "two doses of either vaccine consolidates antibody immunity in infection-experienced individuals," according to the researchers.

Therefore, they summarize, "our data suggest that two doses of mRNA vaccine or a heterologous boosting strategy [with two different vaccine types] are likely to offer the broadest [variant of concern neutralizing antibody] coverage."

The findings by Edward J. Carr, MB BChir, PhD, a postdoctoral clinical fellow in the Crick's Cell Biology of Infection Laboratory, London, UK, and colleagues were published online August 12 in The Lancet.

Patients on Dialysis Unlikely to Be Protected From Delta After AZ Vaccine

Patients on hemodialysis typically have 4-hour dialysis sessions three times a week, which are lifesaving, but also put them at risk of SARS-CoV-2 infection, the researchers note.

"Unfortunately, the risk from COVID-19 has been much greater for dialysis patients as we've seen high rates of admissions and deaths in this group," Carr added in a statement from the Francis Crick Institute.

The current study suggests that "the level of neutralizing antibody to the Delta variant that is made by patients on hemodialysis who have not had a prior COVID-19 infection and received the Oxford-AstraZeneca vaccine might not be enough to prevent infection with Delta," he said.

However, "importantly," the research also showed that patients on hemodialysis without prior infection "respond well to mRNA vaccines and we can use this information to inform future vaccination strategies."

"This is extremely timely research," added Aisling McMahon, PhD, executive director of research, innovation and policy at Kidney Research UK, which cofunded the study.

The findings, she said, "clearly indicate that dialysis patients (who have not previously had COVID-19) are unlikely to be adequately protected from the Delta variant if they received the [AstraZeneca] vaccine."

"We believe that this study provides strong evidence to support a third dose of an mRNA vaccine as standard treatment as soon as possible for all immunocompromised patients who potentially remain at risk," she added.

In an August 10 statement, the World Health Organization highlighted that "in the context of ongoing global vaccine supply constraints," people in some countries cannot obtain a first dose of the vaccine, so a third booster dose "should be firmly evidence driven."

The study is funded by Kidney Research UK, the UK National Kidney Federation, Kidney Wales, the PKD charity, and several patient associations. Carr has reported no relevant financial relationships. Disclosures for the other authors are listed in the article.

Lancet. Published online August 12, 2021. Full Text

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