One of the most frightening things I have read in recent times is a study titled Community Outbreak Investigation of Sars-CoV-2 Transmission Among Bus Riders in Eastern China published in JAMA (Journal of American Medical Association) Internal Medicine. According to this study, by researchers from the US and China, 23 of 67 passengers who took a round trip lasting 100 minutes by bus (in January, in Zhejiang in Eastern China) to attend a 150-minute event were infected by the 68th passenger on the bus (who was unaware about being infected). A few of those who attended the event (and weren’t on the bus) were also infected — and all of them said they had come in close contact with the so-called index patient. The researchers found that those who were on the bus were around 40 times more likely to have been infected than 60 others (none infected) on another bus attending the same event (lending an entirely different perspective to the great Ken Kesey’s quote — “you are either on the bus or off the bus”).A study by researchers from the US and China showed that 23 of 67 passengers who took a round trip lasting 100 minutes by bus to attend an event were infected by the 68th passenger on the bus. The bus was air conditioned and in indoor-circulation mode. And while there were high-risk and low-risk zones, there wasn’t an appreciable difference in the chances of infection of those seated in these — a clear indication of airborne transmission of the virus.
The bus was air conditioned and in indoor-circulation mode. And while there were high-risk and low-risk zones, there wasn’t an appreciable difference in the chances of infection of those seated in these — a clear indication of airborne transmission of the Sars-CoV2 virus, especially in a closed area where the air is recirculating. The attack rate of the virus on the bus was around 34%, the researchers found, although people seated near the door and the one window that could be opened, did not get infected.
The study was published on Tuesday, a day before India’s housing and urban affairs ministry put out guidelines for the resumption of 15 Metro services around the country (13 of these will begin services; two, one in Mumbai and the other in Nagpur, both in the state of Maharashtra which continues to be ravaged by the virus, will not). It isn’t just the Metro; many offices have opened; as have several malls; and some restaurants and gymnasiums. The challenge before all of them is along two dimensions — all arising from the fact that when the facilities (including Metro coaches and stations) were being designed, the emphasis was on optimising space to accommodate the most number of people. In addition, modern malls and offices worked hard on creating social spaces where people could mingle.The first challenge for Metros and modern offices is social distancing. It is not very difficult to ensure the coaches don’t get crowded, but the stations are another matter altogether. The second challenge is the one presented by air-conditioning. Most modern offices have no openable windows and depend on air-conditioning for both maintaining the temperature and air circulation.
The first challenge is social distancing. It is not very difficult to ensure the coaches don’t get crowded, but the stations are another matter altogether. HT reported last week that while Delhi’s buses are sticking to the 20-per-bus limit (by and large) necessitated by Covid-19-related social distancing norms, the stops are crowded, with people waiting for a long time, and then jostling to get into the bus before it reaches its capacity. According to another report in HT, Metro officials will monitor stations through CCTV and order trains to skip crowded stations — an exceptionally well-thought-out solution that assumes the waiting crowd will disperse quietly and in a socially distanced and disciplined manner, instead of continuing to wait for the next train.
The second challenge is the one presented by air-conditioning. Most modern offices have no openable windows and depend on air-conditioning for both maintaining the temperature and air circulation. That is true of malls as well, and Metro stations. The coaches themselves are air-conditioned, simply because many Metros run underground. Experts say that with the right kind of filtration and circulation systems and settings, airborne transmission of the virus can be controlled.
Finally, it all comes down to risk, return, and the absence of options (many people taking buses and the Metro during the pandemic aren’t doing so out of choice).
PS: In a move with significant political undertones, the US Centers for Disease Control and Prevention on Wednesday communicated to all states that they should be ready to store, distribute and administer a vaccine to those at the front lines of the fight against Covid-19, and other vulnerable groups. The communication mentioned two vaccine candidates without naming them, although the New York Times said the specifications match those being tested by Pfizer and Moderna. Three vaccines are in Phase 3 (or combined Phase2/3) trials in the US: Moderna’s, Pfizer/BioNTech SE’s, and Oxford-AstraZeneca’s.