Pre-existing allergic conditions such as asthma or rhinitis may be associated with a higher risk of experiencing long-term symptoms associated with COVID-19, or Long-COVID, according to a study.
A team, including researchers from the University of Magdeburg in Germany analysed published prospective studies of people of all ages with confirmed SARS-CoV-2 infection who were followed for at least 12 months.
The analysis, which appears in the journal Clinical & Experimental Allergy, identified 13 relevant studies -- with a total of 9,967 participants -- published between January 1, 2020 and January 19, 2023.
Although the data as a whole from the studies suggested that individuals with asthma or rhinitis might be at increased risk of Long-Covid after SARS-CoV-2 infection, the evidence for these associations was very uncertain.
The researchers noted that more robust epidemiological research is needed to clarify the role of allergy in the development of Long-Covid.
"We need a better, harmonised definition of what is considered Long-Covid for epidemiological studies of this sort. Regardless we will be updating our analysis once further studies have been published in the next few months, said study corresponding author Christian Apfelbacher, from the Institute of Social Medicine and Health Systems Research at the University of Magdeburg.
The role of allergy as a risk factor for Long-Covid is unclear and has not been thoroughly examined yet, the researchers said.
They aimed to systematically review and appraise the epidemiological evidence on allergic diseases as risk factors for the condition.