New Delhi, May 20 (IANS) The Office of Principal Scientific Advisor to Government of India, Prof K. Vijay Raghavan has released advisory on "Stop the Transmission, Crush the Pandemic - Masks, distance, sanitation and ventilation, to prevent the spread of SARS-CoV-2 virus.The advisory highlights the important role well-ventilated spaces play in diluting the viral load of infected air in poorly ventilated houses, offices etc. Ventilation can decrease the risk of transmission from one infected person to the other.The advisory says that just as smells can be diluted from the air through opening windows and doors and using exhaust systems, ventilating spaces with improved directional air flow decreases the accumulated viral land in the air, reducing the risk of transmission.Ventilation is a community defense that protects all of us at home or at work. Introducing outdoor air in offices, homes and larger public spaces is advised. Measures to improve ventilation in these spaces must be taken up on urgent priority in urban and rural areas alike, recommendations for hutments, homes, offices and large centralised buildings are given.Simple strategic placement of fans, open windows and doors, even slightly open windows can introduce outdoor air and improve the air quality inside. Introduction of cross ventilation and exhaust fans will be beneficial in curtailing the spread of the disease.In buildings with central air-management systems improving central air filtration/increased filtration efficiency is especially helpful when enhanced outdoor air delivery options are limited. In offices, auditoriums, shopping malls etc use of gable fan systems and roof ventilators are recommended. Frequent cleaning and replacement of filters is highly recommended.Saliva and nasal discharged in the form of droplets and aerosols, by an infected person while exhaling, talking, speaking, singing, laughing, coughing or sneezing etc is the primary mode of virus transmissions. infected person who shows no symptoms also transmit the virus. People without symptoms can spread the virus. People should continue wearing a mask, wear double masks or a N95 mask.The SARS-CoV-2 virus infects a human host where it can multiply, in the absence of the host it cannot survive, and stopping the transmission of the virus from a person to another person will decrease the infection rate of the disease to a level where it can eventually die."This can be achieved only with the support and cooperation of individuals, communities, local bodies and authorities. Use of masks, ventilation, distancing, and sanitation, the battle against the virus can be won," it said.--IANSmiz/skp/
Chandigarh, April 22 (IANS) Remdesivir -- an antiviral drug -- does not have any effect in reducing mortality and it is not effective for patients requiring high oxygen support or ventilation, a senior doctor with the Postgraduate Institute of Medical Education and Research (PGIMER) said here on Thursday,G.D. Puri, HoD of Anaesthesia and Intensive Care, PGIMER, said that if the drug has to be rationally used, it should be used within the first seven to eight days in Covid-19 patients developing room air hypoxia, meaning oxygen saturation less than 94 per cent.Remdesivir was the first drug to be approved by the US FDA for the treatment of Covid-19 patients."It is not likely to be beneficial after 10 days in patients who are already on ventilator support. It has a potential to worsen renal functions and may cause arrhythmia, so it needs to be used with caution and under strict monitoring. There are very limited indications of using Remdesivir and a very narrow therapeutic window, so it should be used judiciously," he said.The only medicine with definite effect on reducing mortality in critically ill patients is steroids (dexamethasone), which is beneficial only when Covid positive patients develop hypoxia at room air, Puri said.Use of steroids in patients not having room air hypoxia is associated with the increased risk of mortality. So steroids have to be used judiciously under medical supervision, the doctor warned.On the use of Tocilizumab, he said it is a strong immune system suppressant and is indicated to control "cytokine storms" rapidly. Its use has to be guided by the clinical condition of the patient, Puri said.Since it can increase the incidence of secondary bacterial infections in the patients, it should be used only after ruling out significant bacterial or fungal infections, he added.In case it is not available, good supportive care, steroids and ventilation may be tried, the doctor added.--IANSvg/arm
Speaking to IANS Professor Srinath Reddy, president Public Health Foundation of India said: "While the virus can spread by air even in the open, the flow of air currents will not allow large viral clouds to form and hang around while such clouds can form easily and waft around slowly in closed spaces." He stressed on wearing proper mask and eye protection to prevent from virus entering through nose, mouth or eyes, and ventilation a key ally in keeping the viral load low. Excerpts from the interview:Q: A report recently published in The Lancet stated SARS-CoV-2, is an airborne pathogen, isn't it worrying? If Covid is airborne, wouldn't it require an overhaul of modification of established Covid-19 safety protocols. A: I believe that both droplet and aerosol modes of transmission are important. Droplet transmission occurs in close proximity in open or closed spaces while airborne infection is more likely as viral clouds form in closed rooms. While the virus can spread by air even in the open, the flow of air currents will not allow large viral clouds to form and hang around while such clouds can form easily and waft around slowly in closed spaces. In either case, wearing a proper mask and eye protection is likely to prevent the virus from entering through nose, mouth or eyes. Ventilation is a key ally in keeping the viral load low. Q: The Lancet paper said, "Long-range transmission of SARS-CoV-2 between people in adjacent rooms but never in each other's presence has been documented in quarantine hotels." If this report is accepted by the broad scientific community, then it will have major implications on how people fight Covid-19? A: Viral clouds forming in closed buildings can drift between rooms. Ventilation and facial protection are still the best safeguards. We will need better quality masks or double masking. Indoor ventilation systems have to be improved. Open cross ventilation is ideal. Q: With infectious variants emerging, which can escape the immunity and vaccines, even after a year into the Covid pandemic. Do you think there is a possibility of a third wave, or things would finally begin to settle after this second wave? A: It is difficult to predict the levels of infectivity and vaccine escape future variants will have. We must hope that the inactivated virus vaccine (Covaxin), which presents a bigger platter of viral antigens for invoking an immune response than vaccines which focus only on the spike protein, will have less threat of vaccine escape from variants which develop spike protein mutations. Whether there will be a third wave of serious infections will depend on how fast we strengthen our public health system and how widely we vaccinate. Q: According to genome sequencing data "double mutant" has become the most common variant. However, patterns have not emerged to establish that the double mutant is driving spike in cases amid the on-going second wave. Do you think double mutant will become a dominant variant similar to Kent variant? A: It is possible that a variant which exhibits greater infectivity than the original wild virus will become dominant over time. Given different variants operating now in different parts of India, it is possible that may see patterns of regional dominance by different variants in different parts of the country. The emerging patterns will also depend on how effectively we can contain transmission from now on, within and between states.Q: In the first wave, the cases peaked in September, almost one lakh every day for weeks, but later it declined. Today, there are more than two lakh cases every day. Is it the peak of the second wave and when will it begin to decline? A: This time the pandemic resurfaced in a fully open society, with high levels of mobility and crowded events. Last time the unlocking was in stages and some restrictions continued for several months. So, the surge soared swiftly. How long it will last will not merely depend on models of how the virus behaves but on how we behave. If we can all wear the right kind of masks the right way whenever away from home and crowded events are curbed with resolve, we can see a downward trend in a few weeks. Otherwise, this wave can get stretched over some months. Q: Today, the government claims to have a fairly good idea about which mutated variant is prevalent where, but all of them are increasing. Isn't it a worrying situation? A: A batsman like Rahul Dravid, with a sound 'Wall' like defence, can face a left arm bowler with as much confidence as he faces a right arm bowler. If we wear the right kind of facial protection the right way and avoid super spreader events involving crowds, we can block both the wild virus and its variants from entering our body. If we expose ourselves and play carelessly, we can be bowled leg stump or off stump. We have to determinedly play the right kind of defence- for some months to come. (Sumit Saxena can be contacted at [email protected] ) --IANS <br>ss/dpb
Bhubaneswar, April 7 (IANS) A commercial five-layered mask coupled with social distancing and good ventilation may be key to curtail the spread of SARS-CoV-2, the virus that causes Covid-19, in enclosed spaces like offices, prisons and hospitals, say researchers from the Indian Institute of Technology Bhubaneswar, Odisha.The findings, published in the journal AIP Advances, showed that just breathing or participating in normal conversation, even without the risk of coughing or sneezing, led to a leakage of air droplets from masks. While a commercial five-layered mask showed full front-of-face protection and minimal leakage below the chin, N-95 masks showed leakage in gaps between the mask and nose. The surgical mask also showed leakage from the front. Adding a face shield can restrict droplet spread, the researchers noted.This presents a notable challenge in preventing the spread of the virus, currently witnessing a second wave in India with 12.8 million positive cases, they added."Our findings show the need for good ventilation systems that take into account the 5 to 10 per cent of aerosolised particle leakage that occurs in each breathing cycle as a way to reduce droplet concentration in enclosed spaces," said Venugopal Arumuru from the varsity. "There also is a need for mask design innovation to reduce side and bottom droplet leakage while providing adequate face comfort," Arumuru added.In an experimental setup, a mechanical breathing simulator was connected to a mannequin standing at 5 feet 8 inches tall to simulate regular breath and slightly longer breath typical of healthy adults standing still or involved in moderate activity, like walking, talking, or participating in assembly work. The researchers evaluated the efficacy of various mask types, mask-shield combinations, and only face shield use.A fog generator was filled with a mixture of water and glycerin to emulate the consistency of saliva droplets in the diameter range of 1-10 micrometers to reflect airborne transmissibility. Droplet exposure was illuminated and captured by video camera.The researchers found that with no face covering, droplets from breathing can travel up to 4 feet in five seconds. --IANSrvt/bg
London - New research adds to the growing body of evidence that effective or proper indoor ventilation may be a key factor in preventing the spread of Covid-19 virus.
The study, published in the journal Environment International, found that SARS-CoV-2 is rather moderately infectious and a person would need to remain in a poorly ventilated room for a considerable amount of time to receive an infectious dose of SARS-CoV-2.
"Multiple studies provided quickly strong scientific evidence for successful indoor airborne transmission of Covid-19 in inadequately ventilated environments," said study author Jarek Kurnitski from Estonian Research Council in Estonia.
"The virus is transmitted via saliva droplets with a size from 0.5 micrometres up to a few thousand micrometres produced by a person by talking, sneezing, coughing, or even just breathing," Kurnitski added.
According to the researchers, the point is that small and large droplets act completely differently. Tiny droplets below 5 micrometres do not settle on surfaces, they remain airborne and follow airflow streamlines for tens of metres.
Large droplets above 100 micrometres in diameter fall down like rocks - they do not travel farther than 1.5 metres even by coughing.
The air exhaled by humans contains mainly droplets with a diameter in the range of 1-10 micrometres.
Until this spring, it was held in the medical literature and guidelines that droplets larger than 5 micrometres fall down at the distance of up to two metres (which is why it was concluded that 2-metre social distancing would ensure complete safety).
By now, however, scientists have found out that this was a misconception or even a long-persisting erroneous medical dogma.
Aerosol physics shows convincingly that in reality only droplets larger than 50 micrometres fall down at a distance of two metres, while smaller ones remain suspended in the air and travel farther.
Thus, acknowledging this tenfold error fundamentally changed the understanding of the spread of virus particles and it was realised that the largest number of exhaled droplets travel far and the virus can remain infectious in aerosol particles for up to three hours.
By breaking this medical dogma, researchers also gave an important signal regarding the measures applied to prevent the spread of Covid-19 that led to the paralysis.
"Measures can and must be applied taking into account the known transmission routes, which is why it is important to know that the disease is transmitted by aerosols, i.e. tiny droplets suspended in the air," the authors wrote.
This means that people can get the virus in two ways: in close contact, where the concentration of aerosols and larger droplets in close proximity of the infected person is very high.
"Or farther away in inadequately ventilated rooms, where the concentration of aerosols remains so high that a person can get an infectious dose for example within an hour spent in the same room with an infected person," Kurnitski noted. (IANS)