The World Health Organisation reported more than 230,000 new COVID-19 cases in one day last week ā the worldāsĀ largest daily increaseĀ during the pandemic. The surge has forced governments in many places across the world to order new lockdowns.

This includes Melbourne, which is back in aĀ six-week lockdownĀ after aĀ second waveĀ of new cases exceeded the cityās first peak in late March.
But Melbourneās not the only city to suffer a second wave of the pandemic. Cities including Beijing and Leicester had lifted COVID-19 restrictions, only to re-enforce them when new outbreaks occurred.
So how have other cities gone about their second lockdown, and have the measures been effective in tackling the COVID-19 resurgence? Letās take a look at a few examples.
Though thereās no strict definition of a lockdown, it describes the controls imposed by governments to restrict the movement of people in their communities. Itās often achieved through a combination of police presence and applying public health regulations.
It can be implemented partially, progressively or fully. The latter is called āhard lockdownā when the freedom of entry to, and exit from, either an entire building or geographic area is prohibited or limited.
TheĀ SegriĆ Ā region in Catalonia, Spain re-entered an indefinite partial lockdown on July 4 following a significant spike in cases and COVID-19 hospitalisations.

The Catalan government, in the northeast of Spain, re-imposed lockdown for the SegriĆ county after recording 816 new COVID-19 cases on July 12. (Photo: Ramon Gabriel/EPA/AAP)
The city ofĀ LeicesterĀ in the United Kingdom has gone into a second lockdown after it accounted for 10% of all positive COVID-19 cases in the country at the end of June. The city has been in lockdown for the past two weeks and despite this, the latestĀ dataĀ show an increase in the numbers of cases.
A second wave inĀ BeijingĀ was tackled by increasing degrees of lockdowns. The strictest measures wereĀ limited to a few high-risk neighbourhoods, accompanied by a ring of looser lockdown measures around them.
Read more:Ā Nine Melbourne tower blocks put into āhard lockdownā ā what does it mean, and will it work?
Alongside this was extensive and widespread testing, with a peak capacity of 300,000 tests per day. This approach proved successful ā the cityĀ reported zero new COVID-19 casesĀ on July 7.
While there are increasing examples of a return to some lockdown measures, there are no examples demonstrating the success of a second lockdown ā other than in Beijing ā because itās too early to tell.
When entering a second lockdown, itās useful to consider the lessons learnt from the first. Initial lockdowns in both Italy and India provide cautionary tales on what happens when public messaging and enforcement is flawed.
Italian media published information about internal movement restrictionsĀ a day beforeĀ the Italian prime minister officially announced it and signed theĀ decree. At the time, onlyĀ northern ItalyĀ was heavily affected by COVID-19.
After the news spread, workers and students, many of whom carried the virus, rushed back home across the country, flooding the train stations. Even though the goal was to reduce the spread of the virus, the effects were the opposite. Soon after, it was discovered that new COVID-19 cases in southern Italy wereĀ families from studentsĀ who came home from the north.
Similar panic amongĀ migrant workersĀ occurred in India when the prime minister gave the public only a few hours notice before the start of the lockdown. This is just one reason why Indiaās lockdown has been labelled as āa spectacular failureā.

The city of Leicester was the first in the UK to go into a second, localised lockdown, after recording nearly 10% of the countryās new COVID-19 cases at the end of June. (Photo: Neil Hall/EPA/AAP)
After a lockdown, the majority of the population remains at risk of infection without a vaccine. So as restrictions ease, cases are likely toĀ increase again, leading to a pattern of lockdowns, relaxation and renewed lockdowns
So why canāt governments just aim to eliminate the virus?Ā An elimination strategyĀ requires strict, intensive lockdowns and closing external and internal borders to eradicate local transmission and prevent the virus being imported.
Elimination strategies have worked in only a few countries and regions, such asĀ New ZealandĀ which imposed an early and strict lockdown.
The effectiveness of lockdowns can be diminished by increasing populationĀ fatigueĀ in response to reimposed restrictions.
Lockdowns also have many serious repercussions, including a severeĀ impact on mental healthĀ and the economy. French Prime Minister Jean Castex has ruled out another total lockdown arguing that itsĀ economic and human consequencesĀ are disastrous.
Locking down a given country can cost up to 3% of GDP per month,Ā according toĀ UBS Global Wealth Management.
Itās clear that lockdowns cannot be maintained indefinitely. Thatās why theĀ rapid development of a vaccineĀ to achieve herd immunity, without extensive infection, is critical ā along with the development of drugs to relieve the symptoms of COVID-19.
So how long should Melbourneās lockdown last? The Grattan Institute hasĀ arguedĀ it should continue until there are no more active COVID-19 cases in the community to eliminate the virus ā and after that, should remain in place for another two weeks.
We argue that the duration of the lockdown could be halved if paired with mandatory universal use ofĀ face masks. Wearing masksĀ lowers the risk of spreading and contracting the disease.
This article is supported by theĀ Judith Neilson Institute for Journalism and Ideas.
This article is republished fromĀ The ConversationĀ under a Creative Commons license.
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