[lvlrsSTI]

The Delta variant of the coronavirus has played havoc with governments' plans to return life to some sense of normality.

Fresh outbreaks fuelled by the highly infectious strain have forced major cities in China, Australia, the Philippines and elsewhere back into lockdown and spurred the authorities, particularly in Asia, to reimpose harsh restrictions as low vaccination rates leave people vulnerable to Covid-19.

Economies have taken a hit as manufacturing hubs like Thailand and Vietnam see their supply chains interrupted. Factories making goods for global brands are halting work and potentially missing out on the crucial holiday shopping season in major markets.

The wave of new infections has also seen the likes of Israel, Britain and the United States scramble to reinstate mask recommendations even among the vaccinated, as data emerges to show that more fully vaccinated individuals are also catching the Delta strain, and might be just as likely to spread it to others around them.

The Delta variant, first identified in India, has become by far the most dominant strain in many countries: It now accounts for almost all new Covid-19 cases in the US, Britain, Russia, Germany, South Africa and Singapore, among other countries.

'Breakthrough' cases

Studies show that the variant to date is the fastest, fittest and most formidable version of the Sars-CoV-2 virus, which causes Covid-19.

Scientists estimate that it is roughly 50 per cent more contagious than the Alpha variant first found in Britain, which in turn was about 50 per cent more contagious than the original strain detected in the Chinese city of Wuhan.

It has also proven more potent than its predecessors, capable of infecting fully vaccinated people.

Still, such individuals - even if infected with Covid-19 - remain far less likely than those who are unvaccinated to fall severely ill, require hospital care, or die from any known variant of the coronavirus.

US data shows that infections, hospitalisations and fatalities remain rare among those who are fully vaccinated.

More than nine in 10 of all new cases, hospitalisations and deaths in US states that reported on Covid-19 from the beginning of the year occurred among those who were unvaccinated or yet to be fully vaccinated, according to the Kaiser Family Foundation, a US non-profit organisation that has been collecting and analysing data on Covid-19 vaccinations.

In Singapore, the fully vaccinated made up about four in 10 of all new cases over the past month - a surprising statistic that can be explained by the fact that around 70 per cent of the population have already been fully inoculated, so the probability of encountering an infection in a vaccinated individual is significantly higher.

Aggressive contact tracing and testing measures would also have identified mild or asymptomatic infections that might not have surfaced otherwise.

Significantly, not one of the fully vaccinated people who were infected died, and current data shows that only one is in intensive care.