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Lockdown has minimal impact on virus spread, says Dr Satish Ranjan

Vinson Kurian Thiruvananthapuram | Updated on April 30, 2021

‘Aerosols likely new mode of transmission’

The more than three lakh cases being reported every day and increasing disease severity with high case fatality rate suggests that variants of the Covid-19 virus in India are more virulent and dangerous than those identified in other parts of world.

There are currently 10 variants circulating globally and one of them is B.1.617 first identified in India with double mutations in spike glycoprotein, E484Q and L452R, notes Dr Satish Ranjan, molecular immunologist and Covid-19 scientific consultant based in Germany.

Virus lineage prevalence based on genomic sequencing data available on tracker outbreak.info that uses data from global repository GISAID reveals that four months ago, the B.1.617 variant was present in only 16 per cent sequenced samples.

Raised virulence, immune escape

Currently though, not just the parent B.1.1617 but its three new variants, B.1.617.1, B.1.617.2 and B.1.617.3, are present in over 65 per cent samples sequenced in the last 40 days. Emergence of these three new lineages has added more concern over the possible increased virulence and ‘immune escape.’

Variant (B.1.617) is still classified as variant of interest (VOI). Along with this, other variants of concern (VOC) have been found in samples sequenced from different regions of India.

These include B.1.1.7 (first identified in the UK), B.1.351 (South Africa) and P.1 (Brazil). Presence of these different variants and increasing prevalence of some, especially B.1.1.7, in samples sequenced from some states makes the current situation more complex.

Aerosol mode of transmission

The daily increase in number of Covid-19 cases and the aggravating positivity rate suggests that not only is the rate of spread of virus very fast but the human-to-human transmission is also on at a faster rate.

This excessive high rate of transmission with increased disease severity means that the virus is more virulent, escaping immunity and spreading by other means than previously established mode such as droplets, urine or faecal matter.

This new mode could be ‘aerosols,’ tiny liquid particles from the respiratory tract generated when someone exhales, talks, or coughs. They can float in the air and can contain live viruses unlike droplets which do not float but settle down on ground or any surface in one-two minutes after exhalation.

Virus in air-filters, ducts

When inhaled, these aerosols make everyone vulnerable to viral infection, observes Ranjan. A scientific study recently published in ‘Lancet’ provides strong and consistence evidence that SARS-CoV-2 can remain in air for as long as for three hours with half-life of 1.1h., i.e. it will take at least 66 minutes for half of the virus to lose activity.

Confirmed presence of the virus in air-filters and ducts in hospitals with Covid-19 patients also means that it predominantly transmits in the form of aerosol. The widespread presence of the virus and its ability to spread through aerosols suggest that a lockdown will have minimal to no impact on Covid-19 spread.

Strict imposition

A lockdown without enforced Covid-appropriate behavior will allow the virus to spread. Therefore, adopting a Covid- appropriate behaviour including wearing medial masks (instead of cloth masks) and maintaining appropriate distancing is key to winning the war against the virus, Ranjan said.

Emerging evidence of aerosol mode of transmission require that the surroundings are properly ventilated, air-filters installed in high-risks areas especially hospitals and crowding of any kind banned.

In the same manner, micro-containment zones/areas may be created locally, superspreaders in a locality identified restrictions imposed forcing them to adopt strict Covid-appropriate behaviour.

Emergence of symptoms or testing positive for Covid-19 doesn’t mean that one can start self-medications and consume a mix of drugs including antibiotics, Remdesivir or Tocilizumab (cytokine IL-6 inhibitor) without understanding the disease condition or consulting doctors.

Such panicky reaction merely adds to the severity of the disease. Remdesivir and/or Tocilizumab are not magic bullets, asserts Ranjan. Remdesivir or even plasma therapy should be used on case-by-case basis purely based on severity of disease, high viral load and lung infection.

Avoid mad rush for drugs

With Roche, the manufacturer of Tocilizumab (under brand names Actemra/RoActemra), announcing that the global phase III study of Actemra/RoActemra (Tocilizumab) plus Veklury (Remdesivir) versus placebo plus Veklury did not meet its primary endpoint and several clinical studies also suggesting that Tocilizumab is associated with higher risks of secondary bacterial and fungal infections and therefore higher mortality, the mad rush for these drugs out of panic should be avoided.

Despite the severity and faster spread of the disease, 85-90 per cent of the infected people are still reported to be recovering well. With strict Covid-appropriate behaviour, the spread can be immediately controlled, Ranjan opined.

Covid-appropriate behaviour

“One should assess the exact stage of the disease based on symptoms and respond sensibly in consultation with doctors. This will avoid overburdening of hospitals and proper healthcare services can be provided to moderately and severely sick patients and the case fatality rate reduced,” Ranjan added.

Covid-19 needs to be fought at an individual level by imposing self-restrictions to the true spirit and following strict Covid-appropriate behaviour, Ranjan maintained.

India must learn from the second wave and augment the healthcare facilities on war-footing while ensuring supplies of essential medicines, oxygen and other equipment for future as well, he noted.

Published on April 30, 2021

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