Lockdowns or measures like wearing masks or distancing from crowds may help slow the spread of the coronavirus, but vaccination remains the ultimate answer.
A sustainable economic recovery is attached to a successful vaccination drive, which has already put the US, China, and the UK ahead of the rest of the world both in terms of managing health and putting their economies on a fast recovery track.
Rapid mutations and emergence of fast-spreading variants – the UK, South African and Brazil ones – have added to the global health worries: Are vaccines losing the battle to the deadly virus?
The world is not sitting idle; biologists and immunologists are working to devise new ways to track and tackle those.
Bette Korber, a biologist at the Los Alamos National Lab, who spotted the first mutation a year ago, is now busy attending four Zoom meetings a week to share data with global scientists to stay ahead of the virus.
Though the pathogen is unlikely to be eradicated any time soon, global scientists' community believe that the SARS-CoV-2 virus could settle down as a common cold or an influenza with ability to cause severe disease, requiring regular booster shots.
When viruses replicate and copy their genomes, efficacy of vaccines so far developed comes under question despite the fact that mRNA vaccines for Covid-19 have efficacy rates above 90%, much higher than average flu shots.
Vaccine makers like Moderna Inc, Pfizer and BioNTech have already started trials of booster shots to keep vaccines effective in the face of the mutating virus.
Does it mean that the world will need a new vaccine every year?
"We don't know," answers Paul Duprex, head of the Centre for Vaccine Research at the University of Pittsburgh, in a Bloomberg article.
There are hopeful scenarios too.
Compared to the notorious HIV virus, SARS-CoV-2 mutates at a much slower rate. It will take "a number of years" for the virus to acquire enough mutations to fully escape existing vaccines.
There is a practical limit to how much the virus can mutate and invade human cells.
"Vaccination is going to take the edge off this pandemic in a very substantial way," believes Jesse Bloom, a researcher at the Fred Hutchinson Cancer Research Centre.
While scientists are racing to decode virus variants, the governments across the world are fighting the disease with whatever resources and weapons they already have got in hand.
After repeated exercises of lockdown, isolation, tracking and testing, nations have now concentrated more on vaccination, whose success has been deemed to be a key to economic recovery.
Singapore is maintaining its end-2021 schedule to vaccinate its population against the coronavirus and plans to invite those under the age of 45 from June to get their first jabs. About 18.4% of Singapore's population have received their first vaccine doses, putting the city state near the top in Asia in terms of vaccination rates per capita although it lags behind world leaders like the US, the UK and Israel, according to Bloomberg data.
Roughly 60% of Singapore's senior citizens have obtained the vaccine.
In Europe, the UK saw the highest deaths from Covid-19 and is still reeling from the country's deepest recession in 300 years.
But in vaccination, it has rapidly outpaced the rest of Europe and is in a better position to gradually reopen from 12 April while its neighbours like France are locking down again.
By 20 March, over 27.6 million British adults have received a first dose of a vaccine, while other countries in Europe were questioning the efficacy of AstraZeneca vaccine. The country offers free test kits so that everyone can take a coronavirus test twice a week.
The US expects daily vaccinations to increase to 5 million as the government escalated the drive to check a possible fourth wave of infection.
China aims to be twice as fast as the US.
The Chinese Center for Disease Prevention and Control now aims to get as many as 560 million people, or 40% of its large population, injected by the end of June.
To encourage people to vaccinate, China is making some offers, such as a basket of eggs or shopping coupons, after getting a dose, according to a Bloomberg report.
In Thailand, the most popular resort island Phuket embarked on a mass inoculation programme two months ahead of the rest of the country to attract tourists.
It aims to deliver shots to most of its population to allow vaccinated overseas visitors to roam the island freely, says a Reuters report.
Officials hope the step will help Thailand see a quick rebound in tourism like the Maldives where hotel occupancy rates bounced back to 70-80% despite cases of the virus.
The tiny Himalayan kingdom Bhutan set a world record administering the first shot of vaccine to 85% of its adult population just in a week since 27 March.
Can Bangladesh follow suit?
From 14 April, Bangladesh went into a fresh lockdown, which is just a measure to buy time to prepare for vaccination and healthcare services. But the real solution lies with a successful vaccination, says Dr Mohammad Sorowar, executive director of the Biomedical Research Foundation, Bangladesh.
With a huge population, things are not easy for Bangladesh like those in Thailand and Singapore which have much smaller populations but much more resources than Bangladesh, he adds.
Bangladesh saw an impressive start of countrywide vaccination on 7 February, targeting people aged 40 and above, and 3.11% population have received the first shots of the Oxford-AstraZeneca vaccine. The second dose vaccination started on 8 April and roughly 13% of those who got the first dose completed their second round till Tuesday.
The next phases of vaccination are likely to go slow due to a delay in getting supply from the Indian company Serum Institute.
To reach close to a level of herd immunity, Bangladesh needs to vaccinate 60-70% of its population, which would require at least 120 million doses. "But it is difficult to get the required supply of vaccines because we did not put advance orders for adequate supplies," said the public health researcher.
Global researches indicate that Covid-19 would stay at least until 2025, and countries that would be successful in vaccination would be able to get back to normal life and rebound their economies.
Since availability of vaccines remains much less than required, Bangladesh may prioritise vaccination, he suggested. Apart from aiming to inoculate senior citizens and front-liners, Bangladesh needs to prioritise targeted groups of people, considering economic and social needs – such as teachers and factory workers, Dr Sorowar said.
The private sector needs to be engaged in the drive so that factory owners and private sector employers can initiate vaccination of their workers and employees, said Dr Sorowar, who is also an associate professor at Independent University Bangladesh. This will reduce pressure on the government and make the vaccination drive more participatory.
Besides, initiatives should be taken immediately to facilitate local drug-makers to import Covid vaccines in bulk and package those for local distribution. "It might be possible to produce the Russian vaccine Sputnik V here," he said, stressing the need for widening the scopes to get as many vaccines as possible before mutations make things more complicated.