Opening a pandora’s box?

Contributed by Dr Selwyn Selva Kumar

Halfway through the COVID 19 pandemic, after losing thousands of lives to this lethal virus, over half a year of devastating lockdowns, with still a significant number of new cases filling the hospitals, the country is slowly getting back to the routine. Policy makers are forced to reopen schools, restaurants, offices to ease out financial burden. Is it safe to do so amid ongoing pandemic? With the current knowledge, it is very clear that universal face masking, social distancing and scrupulous hand hygiene is the way to prevent transmission of the disease. Evidence suggests that face masking not only prevents transmission, it also simulates ‘variolation’ where, by reducing the inoculum of the virus, builds the immunity and reduces the severity of the disease.

Dining in restaurants, where face masking cannot be followed, social distancing cannot be implemented with potential to overcrowd, increases the risk of transmission. Post lockdown, positive COVID cases are almost twice as likely to have been reported from dining at restaurants, where ventilation, intensity of air flow might affect virus transmission even if social distancing and mask use are implemented. Investigation of a restaurant outbreak in China revealed that one presymptomatic person infected 9 other diners who sat under the same conditioning vent that circulated old rather than fresh air. How many dine-in restaurants have HVAC (Heat, Ventilation and Air conditioning) system in place? This also explains the alarming rise in new cases in some western countries (Madrid), where indoor dining was open with 60% capacity in June.

Transmission dynamics at schools suggests that children under the age of 10, who contracted the disease had no symptoms or mild symptoms and have potential to transmit to adults at home who might get severe disease. To ensure safe schooling, minimizing transmission, to guard against the potential for schools to act as amplifier within community, WHO recommends multilayered measures. Maintaining one metre distance between students, cohorting, staggering the timings, transportation and reorganization of the physical space, increasing ventilation by opening windows and doors, ensuring availability of masks and symptoms screening are some of the measures that can be implemented. Long term effects of keeping schools open on community transmission are yet to be evaluated. This underscores the importance of rigorous implementation of preventive measures when SARS COV 2 is circulating in the community.

References

  1. Facial Masking for Covid-19 — Potential for “Variolation” as We Await a Vaccine. DOI: 10.1056/NEJMp2026913.
  2. WHO/2019-nCoV/Adjusting_PH_measures/Schools/2020.2