A combination of physical distancing measures including quarantine, shutting down schools and workplace distancing is most effective in controlling the coronavirus pandemic, showed a study released on Tuesday.

While a combination of quarantine and workplace distancing was found to be the second-best option, quarantine and school closure was the next best option.

Researchers used simulation to investigate various early intervention steps required to control the spread of COVID-19 in Singapore. Only quarantine was least effective, according to a first-of-its-kind study published in the medical journal The Lancet.

Singapore has taken a slew of measures to control the outbreak. Still, schools have not been closed despite coronavirus cases rising in the country to 558 on Wednesday.

Researchers suggest that a combined approach could help in preventing a national outbreak at relatively low levels of infectivity.

"The results of this study provide policymakers in Singapore and other countries with evidence to begin the implementation of enhanced outbreak control measures," said Dr. Alex Cook from the National University of Singapore.

"The combination of these measures would mitigate or reduce local transmission rates if deployed effectively in a timely manner," Cook added.

The combined measures could keep the reproduction number (RO) of the virus at 1.5, preventing a national level outbreak.

But if the RO crosses the value of 2.0 to 2.5, "outbreak prevention becomes considerably more challenging," according to the study.

The findings come at a time when a considerable number of countries in a bid to flatten the epidemic curve have imposed lockdowns. But citizens continue to flout the stay-at-home advice.

At the same time, governments have been slow in announcing the closure of schools, bars, and entertainment venues in order to further stop the spread of the virus.

Even in Italy, worst hit by the virus and with a death toll crossing 6,800, people gathered in the street, ignoring the lockdown norms.

More than 92,367 citizens were fined, and videos of mayors scolding people on the street have gone viral on various social media platforms.

Pandemic, lockdowns and vulnerable communities

A similar situation prevailed in the UK and U.S., forcing the closure of bars and entertainment venues, resulting in job cuts.

Governments are announcing financial packages for employees and homeless people to deal with the lockdown.

India announced a 21-day lockdown in the entire country after the number of cases reached 512 on Wednesday.

The government warned of stern action against people loitering on the streets, putting communities at the risk of coronavirus infection.

People in developing countries are facing one of the worst consequences of the lockdown. Thousands of daily wage migrant laborers working in metropolitan cities thronged to railway stations to reach their villages.

Joseph Lewnard and Nathan Lo from the University of California, not involved with the study, suggested governments should consider vulnerable communities when formulating policies.

"Political leaders must enact quarantine and social-distancing policies that do not bias against any population group," they said.

"The legacies of social and economic injustices perpetrated in the name of public health have lasting repercussions."

In order to ease the impact of lockdowns on financially challenged communities, a few state governments in India announced a monthly payment to registered migrant laborers and workers.

But with nearly 50 million people living with 1.90 U.S. dollars a day, a lockdown is likely to impact them severely.

"Interventions might pose risks of reduced income and even job loss, disproportionately affecting the most disadvantaged populations: policies to lessen such risks are urgently needed," added Lewnard and Lo.

"Special attention should be given to protections for vulnerable populations, such as homeless, incarcerated, older, or disabled individuals, and undocumented migrants."

(Cover photo: A health worker watches thermal images to detect passengers who may be infected with coronavirus at Suvarnabhumi International airport in Bangkok, Thailand, January 29, 2020. /AP Photo)