The CUHK medical school has conducted Asia's largest population-based long Covid survey to understand long-term sequelae after contracting an acute Covid-19 infection.

The school surveyed some 10,000 citizens aged between one to 102, who recovered from Covid from July to December last year, with 97 percent of them having been infected by the Omicron variant.

Results showed that 70 percent of the subjects still suffered from at least one long Covid symptom at a median of five months.

Neuropsychiatric symptoms were the most common, with 38 percent of long Covid sufferers reporting poor memory, difficulty in concentrating, slow thinking, insomnia, hypersomnia, anxiety, negative moods, reduced motivation and changes in the sleep-wake cycle. For some, symptoms can last for over three years.

Meanwhile, 12 percent of long Covid sufferers reported reproductive problems - 80 percent of whom were women - including menstrual irregularity, sexual dysfunction or increased sensitivity in the groin area.

If five million Hong Kong citizens have had Covid throughout the three years, the school estimated that about 420,000 may suffer from reproductive health concerns.

One in four surveyed citizens with reproductive symptoms said the problem had a major impact on their interpersonal relationships.

But more than half had not sought medical help or had no access to information on long Covid treatment or prevention.

Some 70 percent felt overwhelmed or helpless in coping with these health conditions.

The school also cited a United Kingdom study that long Covid patients have a two-fold increase in the risk of reduced libido and ejaculation difficulty, while a Covid infection may also disrupt the balance of male reproductive system hormones, leading to infertility problems.

Meanwhile, the survey also found that female recovered patients, patients aged over 45, as well as patients who had a history of Covid-related hospitalization, were among the highest-risk groups of long Covid symptoms.

CUHK medical faculty dean Francis Chan Ka-leung urged that stronger support in the primary healthcare system is needed for referring patients with complex conditions to specialists.

"In the long run, we believe establishing a dedicated long Covid center to manage complex cases will not only provide holistic treatment but also enhance research in its treatment and prevention," he said.

Ng Siew-chien, from the department of medicine and therapeutics, said people should not ignore the debilitating symptoms of long Covid, which can affect physical, mental and sexual health.