Hong Kong's government declared its first lockdown on Saturday, January 23, ordering thousands of people to stay in their homes as authorities tackled an ongoing outbreak of the coronavirus in one of the city's poorest and most densely populated districts, Deutsche Welle reports.

The lockdown affects 10,000 people living in the Jordan neighborhood in Kowloon. Authorities said they planned to test everyone in the designated zone within 48 hours, and the residents will not be allowed to leave unless they can show a negative test.

"Residents will have to stay at their premises to avoid cross-infection until they get their test results," Health Minister Sophia Chan told reporters on Saturday.

Severe reaction to Moderna's Covid-19 vaccine is "rare," US health authorities have found, with only 10 cases of anaphylactic shock among a reported 4,041,396 first doses administered between December 21 and January 10.

Based on this early monitoring, anaphylaxis after receipt of the Moderna Covid-19 vaccine appears to be a rare event," the Centers for Disease Control and Prevention said in a report.

The numbers represent 2.5 cases of anaphylactic shock per one million Moderna injections, compared with 11.1 cases per one million BioNTech-Pfizer injections, according to the CDC study.

Pfizer-BioNTech will ship the first 40 million coronavirus vaccines to poorer nations next month on a non-profit basis, through the globally-pooled COVAX facility. The World Health Organization's COVAX scheme is aimed at 20% of vulnerable populations this year.