Shocking image of dead child washed up on Turkish beach lays bare Europe's migrant crisis

Houston, Mar 15: Researchers, studying the novel coronavirus, have found that the time between cases in a chain of transmission is less than a week, and over 10 per cent of patients are infected by someone who has the virus, but does not show symptoms yet, a finding that may help public health officials contain the pandemic.

The study, published in the journal Emerging Infectious Diseases, estimated what's called the serial interval of the coronavirus by measuring the time it takes for symptoms to appear in two people with the virus -- the person who infects another, and the infected second person.

According to the researchers, including those from the University of Texas at Austin, the average serial interval for the novel coronavirus in China was approximately four days.

They said the speed of an epidemic depends on two things -- how many people each case infects, and how long it takes cases to spread.

The first quantity, the scientists said, is called the reproduction number, and the second is the serial interval.

Due to the short serial interval of the disease caused by the coronavirus -- COVID-19 -- they said, emerging outbreaks will grow quickly, and could be difficult to stop.

“Ebola, with a serial interval of several weeks, is much easier to contain than influenza, with a serial interval of only a few days,” said Lauren Ancel Meyers, study co-author from UT Austin.

Meyers explained that public health responders to Ebola outbreaks have much more time to identify and isolate cases before they infect others.

“The data suggest that this coronavirus may spread like the flu. That means we need to move quickly and aggressively to curb the emerging threat,” Meyers added.

In the study, the scientists examined more than 450 infection case reports from 93 cities in China, and found the strongest evidence yet that people without symptoms must be transmitting the virus -- known as pre-symptomatic transmission.

More than one in ten infections were from people who had the virus but did not yet feel sick, the scientists said.

While researchers across the globe had some uncertainty until now about asymptomatic transmission with the coronavirus, the new evidence could provide guidance to public health officials on how to contain the spread of the disease.

“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” Meyers said.

The researchers cautioned that asymptomatic transmission makes containment more difficult.

With hundreds of new cases emerging around the world every day, the scientists said, the data may offer a different picture over time.

They said infection case reports are based on people's memories of where they went and whom they had contact with, and if health officials move quickly to isolate patients, that may also skew the data.

“Our findings are corroborated by instances of silent transmission and rising case counts in hundreds of cities worldwide. This tells us that COVID-19 outbreaks can be elusive and require extreme measures,” Meyers said.

Washington, May 27: Most viruses and other germs do not spread easily on flights, the US Center for Disease Control and Prevention has said in its COVID-19 guidelines which do not recommend following social distancing between two passengers inside a plane or keeping the middle seat unoccupied.

As a result of coronavirus pandemic, air traffic inside the US has come to a near halt. Air traffic is said to be down to about 90 per cent. For all travellers coming from overseas, the Center for Disease Control and Prevention (CDC) has recommended 14 days quarantine.

"Most viruses and other germs do not spread easily on flights because of how air circulates and is filtered on aeroplanes," the CDC has said in its set of COVID-19 guidelines for air travellers.

However, it noted that the air travellers were not risk-free especially in the time of the coronavirus pandemic and recommended Americans to avoid travel as far as possible.

"Air travel requires spending time in security lines and airport terminals, which can bring you in close contact with other people and frequently touched surfaces," it said.

"Social distancing is difficult on crowded flights, and you may have to sit near others (within six feet), sometimes for hours. This may increase your risk for exposure to the virus that causes COVID-19," the CDC said.

But instead of recommended social distancing inside commercial planes, the CDC has advised a series of preventive and hygienic measures to be taken by the airlines pilot and crew to prevent the spread of coronavirus.

The US Department of Transportation and Federal Aviation Administration in its latest safety alerts for operators on May 11 said that air carriers and crews conducting flight operations having a nexus to the US, including both domestic and foreign air carriers, should follow CDC's occupational health and safety guidance.

The CDC issued its guidelines in first guidelines for the airlines and airline crew on March and again in May.

The CDC, which has issued an exhaustive social guideline measures in various sections, is silent on keeping the middle seat of a plane unoccupied so as to maintain the six feet distance between two passengers.

It calls for the plane crew to report to the CDC a traveller with specific COVID-19 symptoms like fever, persistent cough, difficulty in breathing and appearing unwell.

Asking the airlines and cabin crew to review infection control guidelines for cabin crew, the CDC recommends several measures for cabin crew to protect themselves and others, manage a sick traveller, clean contaminated areas, and take actions after a flight.

Prominent among them include washing hands often with soap and water for at least 20 seconds, particularly after assisting sick travellers or touching potentially contaminated body fluids or surfaces and use of alcohol-based hand sanitizer (containing at least 60 per cent alcohol) if soap and water are not available.

Airlines should consider providing alcohol-based hand sanitizer to cabin and flight crews for their personal use, it said.

The CDC guidelines do not recommend following social distancing inside a plane between two passengers or keeping the middle seat unoccupied. But it asks to minimise contact between passengers and cabin crew and the sick person.

"If possible, separate the sick person from others (by a distance of 2 meters or 6 feet, ideally) and designate one crew member to serve the sick person. Offer a facemask, if available and if the sick person can tolerate it. If a facemask is not available or cannot be tolerated, ask the sick person to cover their mouth and nose with tissues when coughing or sneezing," said the CDC guidelines.

If no symptomatic passengers were identified during or immediately after the flight, the CDC recommends airlines to follow routine operating procedures for cleaning aircraft, managing solid waste, and wearing PPE.

"If symptomatic passengers are identified during or immediately after the flight, routine cleaning procedures should be followed, and enhanced cleaning procedures should also be used," it said.

Clean porous (soft) surfaces (e.g, cloth seats, cloth seat belts) at the seat of the symptomatic passengers and within 6 feet of the symptomatic passengers in all directions, it added.