Explainers & FAQs

More research is needed on the effectiveness of a fourth Covid-19 vaccine shot. Photo: AFP
Explainer | Second boosters: what the studies tell us about the fourth Covid-19 jab

Many countries are offering fourth doses of the vaccines, but most are for at-risk groups like the elderly.

16 May 2022 - 9:26AM
None of the known hepatitis viruses have been identified in the hundreds of cases reported across 20 countries involving young children. Photo: Handout
Explainer | What is the mystery hepatitis affecting children around the world?

20 countries have reported acute liver inflammation in young patients, many of them previously healthy.

14 May 2022 - 3:16PM
China is relying on vaccines with lower efficacy rates. Photo: Xinhua
Explainer | How China’s drive to develop its own state-of-the-art Covid vaccine is going

The country has not authorised any mRNA vaccines, despite their proven benefits, a move many observers believe is down to the wish to develop its own version.

16 May 2022 - 9:25AM
International travellers are now allowed to enter Hong Kong again. Photo: K. Y. Cheng
Explainer | How Hong Kong vaccine pass scheme works if you’ve just arrived in city

From Thursday, all those entering the city will be issued with a ‘provisional vaccine pass’ QR code together with a compulsory quarantine order at border checkpoints.

5 May 2022 - 10:29PM
Some countries have started giving fourth shots of Covid-19 vaccines to vulnerable groups such as the elderly. Photo: Jelly Tse
What are the benefits of a second Covid-19 vaccine booster shot?

Some countries have started giving fourth doses to seniors and other vulnerable people.

8 Apr 2022 - 10:26PM
Mass testing has caught infections early, during the incubation period before symptoms begin, according to the head of Shanghai’s CDC. Photo: AFP
Explainer | Why is Shanghai seeing so many asymptomatic Covid-19 infections?

China is in the grip of an Omicron wave, but about 70 per cent of cases reported in March have not had any symptoms.

11 Apr 2022 - 11:41PM
Travellers show the “health code” on their phones at a railway station in Nanjing, Jiangsu province. Photo: Xinhua
Explainer | The colour-coded Covid app that’s become part of life in China

Critics have raised privacy concerns over the system, saying it’s a way to exercise mass surveillance and social control.

5 Apr 2022 - 7:00PM
The coronavirus mutates rapidly, fuelling its spread. Photo: Shutterstock
Explainer | Will the coronavirus continue to evolve after Omicron?

Scientists believe that further strains will emerge in future given the nature of the virus and the extent it has spread around the world.

4 Apr 2022 - 2:10PM
Britain’s Health Security Agency is monitoring three recombinant lineages: XD, XE and XF. Photo:  Shutterstock
Explainer | What is the XE Omicron hybrid and should we be worried about it?

Researchers have detected a number of recombinant Covid-19 sublineages in Europe

1 Apr 2022 - 8:00PM
There is still much more to know about the long-term effects of the coronavirus. Photo: AP
Explainer | Post Covid syndrome affects millions. There’s little known about its cause

Symptoms can emerge months after the initial coronavirus infection is gone.

29 Mar 2022 - 1:40PM
Authorities have been urging older Hongkongers to get vaccinated. Photo: Felix Wong
Explainer | A closer look at Hong Kong’s home vaccination services for elderly, disabled

Government to start vaccinating homebound residents in need, following Hong Kong Council of Social Service’s pilot programme offering free Sinovac jabs.

10 Apr 2022 - 4:38PM
Inbound travellers arriving at Hong Kong International Airport queuing up to be transported to quarantine hotels in the city. Photo: May Tse
Explainer | Hong Kong’s latest Covid-19 rules for travel and social distancing

Travel restrictions will be eased starting April 1, while in-person classes are set to resume from April 19 and social-distancing curbs relaxed in three phases from April 21.

27 Mar 2022 - 4:30PM
A recruitment board in an industrial building in Ngau Tau Kok has seen job vacancies dry up. Photo: May Tse
Explainer | What financial help can Hong Kong SMEs, unemployed get from government?

Small and medium-sized enterprises, and the unemployed can expect to receive help through the Employment Support Scheme and Temporary Unemployment Relief initiative

19 Mar 2022 - 3:15PM
The use of Paxlovid in Hong Kong’s public hospitals, designated clinics and elderly care facilities will begin on Wednesday. Photo: Reuters
Explainer | How do the two Covid-19 oral drugs molnupiravir and Paxlovid work?

The drugs should be given patients with mild to moderate symptoms within five days of the onset of symptoms

16 Mar 2022 - 9:00AM
Scientists advise taking any approved and accessible vaccine - whether a person has been infected with coronavirus previously or not. Vaccination and a booster will better prevent further infection, according to studies from around the world.
Explainer | Do I still need the vaccine or a booster if I’ve already had Covid-19?

Infection can induce antibodies and cause so-called natural immunity but questions remain about how much protection it offers and for how long.

8 Mar 2022 - 8:12PM
Residents wait in line for BioNTech inoculation at a mobile vaccination station in Shek Kip Mei on Sunday. Photo: Yik Yeung Man
Explainer | A closer look at Hong Kong’s latest rules on Covid-19 testing, quarantine

Changes such as registering positive results using rapid antigen tests on a government portal can help speed up confirmation of Covid-19 infections.

28 Feb 2022 - 4:24PM
Covid-19 tracking and contact-tracing apps have become essential for many people to have on their smartphones to safely carry on outside their homes. Photo: Shutterstock
Must-have Covid-19 tracking apps for international travellers

These apps have become essential for many people to safely carry on outside their homes, while observing social-distancing rules.

28 Feb 2022 - 10:53AM
Residents will have to use the “Leave Home Safe” app for entry into specific premises under the vaccine pass scheme. Photo: Felix Wong
Explainer | What is Hong Kong’s Covid-19 vaccine pass scheme and how does it work?

The scheme, set to launch on Thursday, allows only vaccinated or exempted residents to enter specific premises, with exemptions in certain instances.

22 Feb 2022 - 9:54AM