'Strong evidence' COVID-19 predominantly spreads through air: Lancet study
New Delhi, Apr 16: There is consistent, strong evidence to prove that the SARS-CoV-2 virus, behind the COVID-19 pandemic, is predominantly transmitted through the air, according to a new assessment published on Friday in The Lancet journal.
The analysis by six experts from the UK, the US and Canada says public health measures that fail to treat the virus as predominantly airborne leave people unprotected and allow the virus to spread.
Although some studies in the past have suggested that COVID-19 may spread through air, overall scientific literature on the subject has been inconclusive.
In July last year, over 200 scientists from 32 nations wrote to the WHO, saying there is evidence that the coronavirus is airborne, and even smaller particles can infect people.
"The evidence supporting airborne transmission is overwhelming, and evidence supporting large droplet transmission is almost non-existent," said Jose-Luis Jimenez, from the University of Colorado Boulder in the US.
"It is urgent that the World Health Organization and other public health agencies adapt their description of transmission to the scientific evidence so that the focus of mitigation is put on reducing airborne transmission," Jimenez said.
The team, led by researchers at the University of Oxford in the UK, reviewed published research and identified 10 lines of evidence to support the predominance of the airborne route.
The researchers highlighted the super-spreader events such as last year's Skagit Choir outbreak in the US, in which 53 people became infected from a single infected case.
Studies have confirmed these events cannot be adequately explained by close contact or touching shared surfaces or objects, the researchers said in their assesment.
They noted that transmission rates of SARS-CoV-2 are much higher indoors than outdoors, and transmission is greatly reduced by indoor ventilation.
The team cited previous studies estimating that silent -- asymptomatic or presymptomatic -- transmission of SARS-CoV-2 from people who are not coughing or sneezing accounts for at least 40 per cent of all transmission.
This silent transmission is a key way COVID-19 has spread around the world, "supporting a predominantly airborne mode of transmission," according to the assessment.
The researchers also highlighted work demonstrating long-range transmission of the virus between people in adjacent rooms in hotels, who were never in each other's presence.
On the contrary, the team found little to no evidence that the virus spreads easily via large droplets, which fall quickly through the air and contaminate surfaces.
"We were able to identify and interpret highly complex and specialist papers on the dynamics of fluid flows and the isolation of live virus," said study lead author Trish Greenhalgh.
"While some individual papers were assessed as weak, overall the evidence base for airborne transmission is extensive and robust," Greenhalgh added.
He noted that there should be no further delay in implementing measures around the world to protect against such transmission.
The assessment has serious implications for public health measures designed to mitigate the pandemic, the researchers said.
They said "droplet measures" such as handwashing and surface cleaning, while important, should be given less emphasis than airborne measures, which deal with inhalation of infectious particles suspended in the air.
According to the researchers, if an infectious virus is primarily airborne, someone can potentially be infected when they inhale aerosols produced when an infected person exhales, speaks, shouts, sings, or sneezes.
They noted that some airborne control measures include ventilation, air filtration, reducing crowding and the amount of time people spend indoors.
Wearing masks whenever indoors, attention to mask quality and fit, and higher-grade PPE for healthcare and other staff when working in contact with potentially infectious people are some of the other control measures, according to the researchers.
"It is quite surprising that anyone is still questioning whether airborne transmission is the predominant transmission pathway for this virus or not," said study co-author Professor Kimberly Prather, from the University of California San Diego, US.
"Only by including inhalation of aerosols at both close and long range can we explain the many indoor outbreaks that have occurred around the globe. Once we acknowledge this virus is airborne, we know how to fix it, Prather said.
The researchers added that there are many examples of places that have fared much better by acknowledging this virus is airborne from the start, adding the world needs to follow their lead as soon as possible.
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London, Nov 22: A bomb disposal squad deployed as a “precaution” to the South Terminal of Gatwick Airport concluded an investigation into a "security incident" on Friday after making a “suspect package” safe.
The South Terminal of Gatwick Airport, the UK's second busiest airport after Heathrow, which was briefly shut owing to the incident reopened following the incident.
The Gatwick is around 45 km south of London.
Two people detained during the enquiries have since been allowed to continue their journey as the airport was opened.
“Police have concluded their investigation into a report of a suspect package at Gatwick Airport. Officers from the EOD (Explosive Ordnance Disposal) team made the package safe, and the airport has been handed back to its operator,” Sussex Police said in an updated statement.
“Two people detained while enquiries were ongoing have subsequently been allowed to continue their journeys. There will remain an increased police presence in the area to assist with passengers accessing the South Terminal for onward travel,” the statement added.
Earlier on Friday, the incident caused severe disruption at the busy airport’s South Terminal, while the North Terminal of Gatwick Airport remained unaffected.
“Police were called to the South Terminal at Gatwick Airport at 8.20 am on Friday (November 22) following the discovery of a suspected prohibited item in luggage,” a Sussex Police statement said.
“To ensure the safety of the public, staff and other airport users, a security cordon has been put in place whilst the matter is dealt with. As a precaution, an EOD (Explosive Ordnance Disposal) team is being deployed to the airport. This is causing significant disruption and some roads around the South Terminal have been closed. We’d advise the public to avoid the area where possible,” it said.
Footage on social media taken outside the airport showed crowds of frustrated travellers being moved away from the terminal building.
Gatwick said it was working hard to resolve the issue.
“A large part of the South Terminal has been evacuated as a precaution while we continue to investigate a security incident," the airport said in a social media post.
“Passengers will not be able to enter the South Terminal while this is ongoing. The safety and security of our passengers and staff remain our top priority. We are working hard to resolve the issue as quickly as possible.”
Train and bus services that serve the airport were also impacted while the police carried out their inquiries.
In an unrelated incident in south London on Friday morning, the US Embassy area in Nine Elms by the River Thames was the scene of a controlled explosion by Scotland Yard dealing with what they believe may have been a “hoax device”.
“We can confirm the 'loud bang' reported in the area a short time ago was a controlled explosion carried out by officers,” the Metropolitan Police said in a post on X.
“Initial indications are that the item was a hoax device. An investigation will now follow. Some cordons will remain in place for the time being but the majority of the police response will now be stood down,” it added.
