A migrant labourer with her child returning to the city for work looks for transport in New Delhi(AP Photo/Manish Swarup)
High humidity can extend the airborne lifetime of medium-sized virus-laden droplets by as much as 23 times, according to a study which suggests that maintaining physical distancing would significantly remediate the spread of COVID-19.
The novel coronavirus that causes COVID-19 is thought to spread through natural respiratory activities, such as breathing, talking and coughing, but little is known about how the virus is transported through the air, the researchers said.
The study, published in the journal Physics of Fluids, analysed how airflow and fluid flow affect exhaled droplets that can contain the virus.
The model developed by researchers at the University of Missouri in the US includes a more accurate description of air turbulence that affects an exhaled droplet’s trajectory.
“If the virus load associated with the droplets is proportional to the volume, almost 70 per cent of the virus would be deposited on the ground during a cough,” said study author Binbin Wang.
Coronavirus vaccine update
India has asked developers of three vaccines that are currently undergoing human trials in the country to disclose estimates of the price at which their respective vaccines can be made available.
Two Indian companies, Hyderabad-based Bharat Biotech and Ahmedebad-based Zydus Cadila, are carrying out phase-1 and phase-2 human trials of their vaccine candidates. A third candidate, being developed by pharma major AstraZeneca and Oxford University, has also been approved for human trials in India, which are expected to begin soon.
NITI Aayog member V K Paul, who also heads the national expert group on vaccine administration, on Tuesday said the trials of the three vaccine candidates were on track, and that it was being reviewed regularly.
Pricing is perhaps complex because some of them (candidate vaccines) are at an early stage (of development). This information will be refined as we move along. There is no firm information. But we have asked about the price range (of the potential vaccines) from individual manufacturers, Paul said.
Pune-bases Serum Institute of India, the worlds largest manufacturer of vaccines by volume, has entered into an agreement with Bill and Melinda Gates Foundation which will enable it to make vaccines available for about Rs 240 per dose. According to this agreement, Serum would produce 100 million doses of one of the vaccines that would eventually become successful for supply to middle and low income countries. It is expected that at least 50 per cent of this tranche would be supplied within India.
Meanwhile, state-owned Chinese company Sinopharm has claimed that a candidate vaccine it is developing would be available in the market by December this year, and would be priced lower than 1,000 yuan (about Rs 10,000) for two doses, according to a report in The Global Times.
The vaccine being developed by Sinopharm is in phase-3 human trials which is being carried out in United Arab Emirates. It is one of the six Chinese vaccines that are currently undergoing human trials.read more
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