March 30 (Reuters) - Here's what you need to know about the coronavirus pandemic right now:

COVID cases in Asia surpass 100 million

Coronavirus infections in Asia passed 100 million on Wednesday, according to a Reuters tally, as the region records a resurgence in cases, dominated by the BA.2 Omicron sub-variant.

The region is reporting more than 1 million new COVID-19 cases about every two days, according to a Reuters analysis. With more than half of the world's population, Asia contributes 21% of all reported COVID-19 cases.

Shanghai expands lockdown

Authorities began locking down some western areas of Shanghai two days ahead of schedule, as new COVID-19 cases in China's most populous city jumped by a third despite stringent measures already in place to try to stop the virus spreading.

Home to 26 million people, China's financial hub is in the third day of a lockdown officials are imposing by dividing the city roughly along the Huangpu River, splitting the historic centre west of the river from the eastern financial and industrial district of Pudong to allow for staggered mass tests.

Frustrated residents have taken to social media to vent, questioning the practicality of persisting with China's zero-tolerance approach to COVID-19.

Chinese truck drivers hoping to outwit COVID-19 inspectors are faking travel histories to get through checkpoints or avoid quarantine, state media reported.

Hong Kong leader says city's brain drain is 'unarguable'

Hong Kong leader Carrie Lam said it was "unarguable" that the global financial hub was seeing a brain drain due to stringent coronavirus rules, but added she valued the city's international status and envisioned a "better development" after the pandemic.

Lam's comments come amid a backlash from businesses and residents who see the rest of the world shifting to living with the virus while Hong Kong officially sticks to a dynamic-zero COVID-19 strategy to curb all outbreaks as soon as they occur.

Indonesia seeks longer shelf life donations as 19 million COVID shots expired

Nineteen million doses of COVID-19 vaccines in Indonesia's national stockpile have expired this year and 1.5 million more are set to expire next month, as donated shots arrive with a short shelf life, a health official said on Wednesday.

Indonesia and many other developing nations are ramping up their vaccination campaign, aided by donations from wealthy countries, but they have been calling for donations with a longer shelf life.

U.S. authorizes second COVID booster for Americans 50 and older

U.S. health officials on Tuesday authorized a second booster dose of the two most commonly used COVID-19 vaccines for people age 50 and older, citing data showing waning immunity and the risks posed by Omicron variants of the virus.

The U.S. Food and Drug Administration agency said the new boosters - a fourth round of shots for most vaccine recipients - of the Pfizer/BioNTech and Moderna vaccines are to be administered at least four months after the previous dose. They are intended to offer more protection against severe disease and hospitalization.

BioNTech to expand trial programme for more anti-Omicron vaccine options

BioNTech has expanded an ongoing clinical trial programme to develop new vaccines and patterns of administration for better protection against the dominant Omicron variant.

BioNtech boosted the number of participants in the trial - in which participants' blood will be monitored for immune responses - to 2,150 from the 1,420 announced in January. (Compiled by Linda Noakes; Editing by Alex Richardson)