Japan's health ministry is conducting a survey on the apparent aftereffects of coronavirus infections.

Around 4.6 million people around the country had been infected with the virus by the end of March amid the sixth wave of infections. Many continue to suffer from such symptoms as abnormalities in their sense of taste or smell, fatigue or impaired concentration, months after they were first diagnosed.

In view of this, the health ministry began a study this month to get a better understanding of the aftereffects. It has a budget of 200 million yen or around 1.6 million dollars.

The researchers are trying to determine the actual long-term symptoms and what triggers them.

The ministry plans to revise a set of guidelines on how to diagnose patients with apparent aftereffects and how to help their rehabilitation by incorporating the latest knowledge. The ministry hopes that people troubled by the aftereffects will be able to get help more quickly in their local medical institutions.

Health officials admit that much remains unknown about the aftereffects of COVID-19. They say they will work harder on the issue so that people can receive appropriate treatment.