The Malta Independent 8 August 2020, Saturday

Covid reproduction number now at 0.91, may exceed 1 if cases increase consistently – Marmara

Albert Galea Sunday, 2 August 2020, 07:30 Last update: about 6 days ago

Malta’s reproduction number for the COVID-19 pandemic currently stands at 0.91, however it may exceed 1 if the number of cases continues to increase consistently in the coming days, statistician Vincent Marmara told The Malta Independent on Sunday in his weekly video blog.

The reproduction number of the virus is one of the key figures which countries across the world have been trying to reduce ever since the COVID-19 pandemic began. The aim for countries has been to reduce the ratio to a level of 1 – which would mean that one person would transmit the virus to one other person.

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There has been a lot of discussion on the current situation in Malta pertaining to COVID-19 after cases continued to spike throughout the past week.

As of Saturday, Malta has 171 active cases of the virus – with the spike largely down to two particular clusters of cases related to a weekend-long party called Hotel Takeover and the Santa Venera village feast respectively, and also down to a high number of migrants rescued throughout the week testing positive for the virus.

In fact the number of migrants who have tested positive so far stands at 88.

On these migrants, Marmara noted that even though they are being counted with Malta’s number of cases, they do not have any bearing on the country’s reproduction number.  This is because the migrants were isolated immediately upon arrival.

Marmara noted that the fact that the majority of the new cases form part of the two other clusters also has an effect on the reproduction number.

As of Friday, 35 cases out of the 53 new ones in the past week were related to the two clusters, Marmara observed.

He noted that it is not the first time that Malta has had to deal with clusters of the virus, noting that there had been a sizeable cluster of cases related to a group of construction workers in the past which had been controlled but which had resulted in an increase in cases.

At that point, Marmara noted, a lot of people had said that the reproduction number had exceeded 1 – something which was incorrect, because one must wait for some days to pass in order to see what the impact of that cluster was on the community as a whole.

It is the same this week – one must wait a few days before seeing whether the clusters have caused increased and sustained transmission in the community.

What is also important is on what data to consider in the cycle to calculate the reproduction number, Marmara noted.

Past information, he said, is important as a source of information for mathematical modelling, and one must be careful in terms of what data to exclude from such calculations.

Marmara noted that as things stand, when excluding the clusters, the situation is not as alarming as some people are seeing it. However, these days are important to take into account: if there is a consistent increase in cases, then the reproduction number will exceed 1.

He added that the authorities have worked well to control all clusters, including these, and there is no reason not to trust them, noting that many had praised Malta for their handling of the pandemic.

He reminded that one must wait a few days before reaching the conclusion on which data should be considered for a new cycle so to see the effect that each particular cluster had on the community.

“We must be cautious and prudent so that we give the most factual and scientifically correct information without causing any extra alarm,” Marmara concluded.

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