High BP may double Omicron severity risk, even after booster dose: Study

Having high blood pressure more than doubled a person's risk for hospitalisation from an Omicron-variant -- despite full vaccination, including a booster dose of the Covid vaccines, according to new research.

The findings showed that individuals with high BP were 2.6 times more likely to require hospital care for severe Covid illness, even when the person had no other serious chronic health condition, the researchers noted in the paper published in the journal Hypertension.

Further, older age, high BP, chronic kidney disease, heart attack, heart failure and the time between the last vaccination and Covid infection were all associated with greater risks of hospitalisation.

"Our data found that it is not just older adults with other underlying health conditions who are vulnerable," said lead author Joseph E. Ebinger, Assistant Professor of cardiology at the Centre's Smidt Heart Institute.

"Breakthrough Omicron infection severe enough to cause hospitalisation can happen to an adult of any age, especially if a person has high blood pressure, even if they have no other major chronic disease. The people who are most at risk are not necessarily who we think they are. They are not the sickest of the sick, and this was a surprising finding," he added.

Researchers conducted a retrospective cohort study of 912 adults who had received at least three doses of an mRNA Covid vaccine (either the Pfizer-BioNTech or Moderna) and were treated for Covid-19 during an Omicron surge, between December 2021 and April 2022.

The analysis found that of the 912 adults who received three doses of an mRNA Covid vaccine, nearly 16 per cent required hospitalisation. Of the 145 patients hospitalised, 125 of them (86.2 per cent) had high BP.

"We need to raise awareness and understanding that receiving three doses of a vaccine may not prevent severe Covid-19 in everyone, especially among people with high blood pressure. We also need more research to understand why there is this link between high blood pressure and an excess risk for more severe Covid-19 illness," Ebinger said.

Researchers said further study is warranted on how to reduce risks for serious Covid infection, whether through more tailored vaccine regimens, new therapeutics or a combination approach.