It was anticipated at the beginning of the pandemic that COVID would be a trigger of aHUS. Global Action postulated it in March 2020.
That is now generally accepted even if there is incomplete understanding of how this “second hit” works.
Similarly a vaccination against COVID would likely be a trigger of aHUS as other vaccinations have been in the past.
Similarly a COVID infection and the vaccine could trigger the other primary TMA, TTP.
A recent study by the Pujan Moradiya group has looked at all the reports of COVID related to primary TMAs with enough detail to analyse the outcomes in “complement mediated HUS/TMA/ aHUS” as the group described aHUS and TTP patients and compare the relative impacts.
The full article can be accessed HERE.
The group found 84 cases of aHUS following a COVID infection or vaccination with enough data for analysis.
All aHUS cases were new not a relapse. Not so for TTP patients.
Of the 84 cases , 65 were triggered by infection whilst only 19 were triggered by vaccination. So better to be vaccinated ?
Men and women were affected almost equally by infection aHUS but in vaccination aHUS nearly twice as many patients were female.
3 in 4 of the aHUS patients needed dialysis for the resulting acute kidney disease. So a very serious manifestation for most. Nearly 50% of infection patients ended up with Stage 3 kidney disease or worse. In the vaccination group 75% recovered with Stage 1 or 2 kidney disease.
COVID infection aHUS was experienced broadly the same across all age groups. Most patients experienced only mild COVID symptoms. But the aHUS symptoms would present in about 5 days.
Nearly 50% of vaccination aHUS was in the over 60 years age group.
Around half of those with an infection and who had been genetically tested had predisposing genetic variants.
In the vaccination cases just over 80% were found to be predisposed. Mostly with C3 variants. The most common vaccination was Pfizer’s. The highest onset was after the first dose and falling off with subsequent doses.
Roughly half of all patients were able to access eculizumab.
Severity of COVID infection, older age and need for acute dialysis were predictors of the worse outcomes for aHUS patients.
Those who know they are or could be predisposed to aHUS ,particularly if older in age and with C3 mutations could prepare for COVID triggers from infection or vaccination even with mild symptoms by watching for symptoms of aHUS at around five days , checking urine for any evidence of TMA affecting kidney function, and alerting their doctors about a possible onset and present to care as quickly as possible to get treatment if they have concerns which materialise.
Whilst the aHUS experience with COVID is not good TTP patients experienced worse outcomes than aHUS patients. Over 30% of patients were still in relapse or had died at last follow up.
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Article No. 679
