Living with a global pandemic for over a year has forced many people all over the world to learn coping mechanisms to keep themselves and their families safe, while carrying on with work and life.
New habits have been ingrained, and many aspects of pandemic living have become familiar. In Singapore, donning a face mask is becoming as natural as wearing shoes before going out. Whipping out your mobile phone to check in at public places via the TraceTogether app and scanning your temperature are now automatic reflexes.
But 16 months into the spread of the coronavirus that causes the Covid-19 disease, dangerous new variants of the virus are emerging. These variants behave differently, calling for changes to the way we humans behave, if we are to keep their spread in check.
So what is different about the outbreaks this time round and how might we have to change our habits?
In Singapore, clusters of cases have emerged in recent weeks, many linked to variants from overseas. The one of greatest concern is the B1617 variant that originated from India. From what is known so far, its traits merit a stricter, tighter public health response.
Understanding the basics of this strain, and figuring out what has changed this year compared with last year in the fight against Covid-19, helps citizens put government advisories into context, so they can figure out how to regulate their social and personal behaviour to contribute to the containment effort.
What has changed: New variant spreads more easily
The B1617 strain was first detected in India in October last year. It is described as a "double mutant", referring to two mutations on the outer "spike" portion of the virus that attaches to human cells. The mutations appear to make it more transmissible (spread more easily) and to help it elude antibodies and the body's natural immune response.
In India, more than 25.5 million people have been infected with Covid-19, and over 280,000 have died. The World Health Organisation, which described B1617 as a variant of global concern, says it has spread to at least 49 countries, including Singapore.
It rapidly becomes a country's dominant strain once it arrives. In Britain, the number of infections has risen 75 per cent since May 13, and the B1617 variant is expected to become the dominant strain in the next few days, forcing a rethink of plans to reopen the economy. In Singapore, 10 cases of infection from the B1617 variant were found as at May 3.
While Singaporeans have asked why the Government did not shut its borders to India until April 24, even countries that shut their borders have not been immune.
Australia shut its borders to all but its citizens and permanent residents in March last year. Among this group are many of Indian origin who would have flown home to Australia in the intervening months.
According to The Wall Street Journal: "In Australia, the B1617 variant made up 40 per cent of the samples collected over the week ended April 15, compared with 16.7 per cent a month earlier, according to Covid CG, a tracking tool from the Broad Institute of MIT and Harvard."
The B1617 strain also appears to attack younger children more, which explains why Singapore moved schools to full home-based learning this week. And as with earlier strains, many who are infected develop mild flu-like symptoms, or have no symptoms, so won't know they are sick, and pass it on to others unwittingly.
The above facts explain why the Government stopped dining in and imposed a two-person cap on public gatherings. As Health Minister Ong Ye Kung said, the experience of the last 16 months has shown that "the most common mode of transmission is still unmasked in a crowded environment with a lot of vocalisation and interaction, and in an enclosed space, especially when ventilation is not good".
This was why "we deliberately removed activities that are taking place in those settings", he explained.
Clear evidence it can infect those who are vaccinated
Many Singaporeans have noticed that recent cases here included several who were vaccinated.
Studies from India show the new B1617 variant does indeed infect people who have been vaccinated.
Data from the Indian Council of Medical Research up to April 21 showed that 0.02 per cent to 0.04 per cent of vaccinated people were infected with Covid-19. This translates to about two to four people per 10,000 population. The study was done among healthcare and front-line workers, who are considered higher risk. So the breakthrough infection rate for the general population may be lower, said Indian experts quoted in India Today.
In Singapore, as at May 10, 30 local fully vaccinated people tested positive for Covid-19. Another 24 imported cases involved people who were already vaccinated. With about 1.2 million residents having received two doses of the vaccine, the 30 local cases suggest a breakthrough rate of 0.000025 or one in 40,000 of those vaccinated getting infected.
Such breakthrough infections are not surprising, because vaccination reduces risk of infection and severe disease if infected, but does not prevent infection.
As former health minister Gan Kim Yong said on May 11: "Most of our local cases of infected vaccinated individuals were asymptomatic. None had severe Covid-19 disease requiring more intensive care."
This suggests that vaccination worked, he said, adding: "Without vaccination, the infection among healthcare workers would have been much worse. While vaccine breakthroughs are possible, vaccines can help to prevent severe illnesses... It is clear that vaccination is most effective when it is part of a whole suite of precautionary measures, such as mask wearing, safe distancing, accurate testing, thorough contact tracing and timely isolation."
Airborne mode of transmission now considered
Another shift in thinking is about the mode of transmission. The American authorities now explicitly warn that the coronavirus can be spread by inhaling fine respiratory droplets and aerosols (tiny particles or droplets suspended in the air). This means the virus can be carried in particles that can travel some distance through the air.
Such airborne spread is in addition to spreading through contact with sprayed droplets or touching one's mouth, nose or eyes with contaminated hands.
The New York Times reported on May 7: "The Centers for Disease Control and Prevention now states explicitly - in large, bold lettering - that airborne virus can be inhaled even when one is more than six feet away from an infected individual. The new language, posted online, is a change from the agency's previous position that most infections were acquired through 'close contact, not airborne transmission'."
Finance Minister Lawrence Wong, co-chair of the multi-ministry task force on Covid-19, alluded to this when he said at Tuesday's press conference: "We know that the new variants are much more infectious than what we had to deal with last year, and there is growing evidence that the new variants can spread through aerosolised particles, which means that all the precautions we are used to, in fact, may not be sufficient to safeguard against the spread of the virus, and we need even more stringent measures."
The greater risk of spread via aerosols - particles suspended in the air that can linger for hours - in part explains the changed advisory on face masks. Singaporeans are now urged to wear masks with better filtration, such as disposable surgical masks, or reusable cloth masks with at least two layers.
How can a society protect itself from a virus that spreads easily, including through the air?
The short answer is: with great difficulty.
A total lockdown with people banned from leaving their homes might do the trick, but that would be drastic especially if prolonged.
Even a circuit breaker of the kind experienced last year will not stamp out the virus. After all, while public gatherings were banned and offices and schools were shut, public transport remained operational, supermarkets remained open, and eateries still did takeaways and deliveries. A highly transmissible, airborne virus can still spread in those circumstances, for example through transient contact at a supermarket or on public transport.
No government can guarantee citizens a city that is virus-free. Increasingly, societies will have to learn to live with Covid-19, but do their best to keep infection numbers low and contained, so severe cases do not overwhelm the healthcare system.
The good news is that Singapore is better equipped than a year ago to deal with Covid-19. There is now a vaccine. Mr Ong said at Tuesday's press conference that close to two million people have been vaccinated, of whom 1.4 million have received both doses. By delaying the second dose going forward, the plan is to have 4.7 million people vaccinated with at least one dose before the end of August.
Getting as many people protected by vaccination as quickly as possible, while containing the spread of Covid-19: Increasingly, this is how societies will have to live with the virus in their midst, and accept the risk of community infections.
As Mr Wong said: "If there is a scenario where the virus never goes away, it becomes endemic to the population and, by then, maybe towards the end of the year, we have a very high proportion of Singaporeans and people in Singapore vaccinated, then how might we think about dealing with the virus and living with the virus as a reality in our lives? So that's something that we are thinking about, but it's something down the road."
But for now, he said, the priority is to stabilise the cases that have surfaced and see if the tighter measures introduced are sufficient to prevent wide spread.
What it all means for individuals
At the authorities' level, the system is in place to monitor the spread and isolate each case detected. The widespread use of TraceTogether and SafeEntry means contact tracing is faster and more comprehensive. Mr Ong said that in the past week, 35,000 swabs were done a day. The laboratories' capacity is 73,000 tests per day. Such fast mass testing means being able to sieve out infected cases to isolate and ring-fence them to prevent further spread.
While the authorities set up their arsenal to battle the virus, individuals too have a key role to play in the coming weeks.
What the above means for you is that if you go out more often, you are more likely to pick up the infection randomly from someone you have contact with, even if it is for a short period and both of you are masked. The earlier Covid-19 strains, being less transmissible, required more prolonged contact to spread. In other words, if you go out, the risk of getting infected today is higher than a year ago.
This is why the Government's consistent message is: avoid going out.
Mr Wong said: "Stay home and go out only for essential activities. I think that will certainly help to break the transmission chain because if you are at home, you're not going out, then there is no likelihood for the virus to spread."
Prime Minister Lee Hsien Loong echoed the advice on his Facebook page on Tuesday: "Vaccinated or not, do stay home as much as possible, to reduce possible exposure to the virus. If you must head out, make sure to wear a mask with good filtration efficiency, such as those issued by the People's Association or Temasek Foundation."
Such words sound as clear a warning as any that venturing out carries a real risk of infection, and passing it on to others.
Each person's definition of what constitutes "essential" activities will differ. For some, it means a weekly grocery shopping trip; for others, thrice-weekly outdoor runs; or even daily visits to eateries for takeaway food. Some, especially the elderly who cannot get vaccinated for medical reasons, have stopped going out for months.
If we took pains last year during the circuit breaker to be careful, to mask up and sanitise our hands often, we have to be doubly vigilant now.
The new variant is a sly enemy. It spreads more easily; it can spread through the air via droplets; and you can get it without even knowing it and pass it on to others. Not much is known yet on whether it is more virulent (more likely to cause severe disease) or more deadly (more people will die from it). But it's better not to take chances.
For Singapore, the race is between the vaccination drive and the spread of the virus.
Staying home to reduce the spread now helps protect all of us, especially the younger population and children who are not yet vaccinated.
The coronavirus is known among scientists as a quick-change artist due to its ability to mutate fast. In this fight, humans have to be as adept and adaptable as the virus in changing their behaviour.