Shanghai citizens are tested for the coronavirus on March 28, 2022. (Photo: Xinhua/VNA)

Based on what scientists know now, the most likely scenario is that the COVID-19 virus continues to evolve, but the severity of the disease it causes diminishes over time as immunity increases due to vaccination and infection, Director-General Tedros Adhanom Ghebreyesus said during a briefing.

The US Centers for Disease Control and Prevention (CDC) reported that the BA.2 Omicron sub-variant is dominant because of its greater transmissibility. US regulators suggest that people with compromised immune systems and people over 50 get a fourth dose of COVID-19 vaccine, at least four months after their third dose.

New cases in Asia surpassed 100 million on Wednesday as the region endures a new surge driven by the BA.2 Omicron sub-variant.

According to worldometer.info, 487 million COVID-19 infections and 6 million deaths had been recorded worldwide as of Thursday. The US has been hit the hardest, followed by India and Brazil.