The delta variant is more contagious, but the way the virus is transmitted does not change

In several countries of the world it has already become prevalent, while in others it is starting to spread. Some episodes in Australia cause concern about how the Delta variant is transmitted

Photo: Matteo Jorjoson / Unsplash

The variant Delta di Sars-Cov-2, with her greater contagiousness, seems destined to become the dominant variant worldwide in a short time, as has already happened in the UK. If in countries where the prevalence of this variant still appears under control (remember that in Italy, according to the last bulletin of the Higher Institute of Health it is equal to 16.8% of infections, with an increasing trend) we are preparing to face it, the news coming from other states on the transmission mode of the Delta. In particular in Australia, the health authorities speak of the risk of contagion even in the case of “fleeting encounters“. Let’s see better why, in reality, the transmission of the coronavirus would always seem the same.

First identified in India, the Delta (also known as B.1.617.2) is one of several variants of concern, designated by the WHO. Spreading rapidly in India and the UK, it now poses a threat to other countries, particularly in places where vaccination rates remain low. According to Public Health England (Phe), at the end of May Delta became the predominant variant in the UK, supplanting the Alfa variant, and one studio in pre-print (which has not yet been subjected to peer review) would confirm this trend also in the United States of America. Always according to the Phe, Delta would have, with respect to Alpha, a c40-60% greater apacity to transmit person to person and would increase by 2,5% the risk of develop Covid-19 in a severe manner. All the countries that have not yet been affected by the spread of this variant are preparing, above all accelerating the vaccination campaign: several studies, in fact, suggest that, while Delta is quite resistant to a single dose of vaccine, the complete vaccination cycle would seem to offer effective protection even against this variant.

What’s happening in Australia

In Australia four of the eight capitals are now in lockdown because of Delta variant, while health authorities try to contain the spread of the virus. In particular, the premier of the Australian state of New South Wales, Gladys Berijiklia, described how meetings “frighteningly fleeting”Those that led to the spread of Delta in Sydney. In fact, the Australian Ministry of Health has come into possession of one shot by a CCTV camera in shopping center Bondi Junction Westfield, in cui two people, later tested positive for the Delta variant, they crossed briefly. According to site of the Australian Ministry of Health, from 16 June 2021, when the first positive for the Delta variant was identified, to date have been identified 160 almost belonging to the so-called cluster Bondi. What worries the most, however, is how it came about spread of the virus. “In a tape, we actually have the tape of the meeting and it’s basically a two-person crossbreedState medical director Kerry Chant said ad Abc.netThey are clearly facing each other, but they are literally two people crossing each other momentarily. Close, but for a moment”.

Queensland medical director Jeannette Young announced that the state it would close its borders to people from Sydney’s Delta variant hotspots. “With the Delta variant, we are seeing very fleeting contacts leading to transmissionYoung told the Guardian. “At the beginning of this pandemic, I stated that 15 minutes of close contactor they could be a concern. Now it seems they are 5 to 10 seconds to worry. The risk is much higher now than it was just a year ago“. What would emerge from the Bondi cluster cases and from the statements of the Australian health authorities, therefore, would be a concern related to transmission mode of the Delta variant, which would happen through the aerosol and with a shorter exposure time. This, however, has not yet been found by any studies.

Hassan Vally, associate professor at La Trobe University, stressed to the Guardian that although the Delta variant is more contagious, even the original Sars-Cov-2 strain could be transmitted through a fleeting contact. WHO made it official in April 2021, but already before several evidences were in support of the transmission be attraverso i droplet (small liquid particles emitted when coughing, sneezing, talking, singing or just breathing), either, through the aerosol, in closed environments poorly ventilated, or crowded, where people tend to spend longer periods of time. For example a shopping mall like Bondi Junction Westfield. “The variant is a little more transmissible, but behaves the same way as the original virus“, continues Vally. “All the same behavioral interventions they should work against this variant of the virus if they worked against the original“. And therefore: distancing, masks especially in closed places, and speeding up the vaccination run.

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