2-day work week, two-tier contact tracing can suppress virus transmission: Analysis
A two-member team of professors at the Chennai Mathematical Institute and Indian Institute of Science (IISC), Bengaluru, has carried out a mathematical analysis of lockdown data from Bengaluru which suggests a two-tier contact tracing strategy and the option of a two-day work week could help suppress the transmission of Covid-19 and shorten the epidemic’s duration.
With Bengaluru as the study area, V Vinay, co-founder of tech start-up Ati Motors, with Chiranjib Bhattacharyya, a professor at IISC, performed simulations of different post-lockdown strategies for their paper titled “Suppress, and not just flatten: Strategies for Rapid Suppression of Covid-19 transmission in Small World Communities”. One of the strategies they suggest is “tracing contacts and their contacts and sealing” (TC2S), which reduces the virus’ attack rate by more than 30% compared to the current approach. TC2S involves identifying and testing all individuals who came in contact with a patient — as is the current method — and also tracing their contacts.
“Lockdowns, though an effective policy for containment, impose a heavy cost on the economy,” said Vinay. “Our study provides alternatives to lockdown which are either more targeted or allow partial opening of the economy.”
According to their analysis, with TC2S, the epidemic would last 274 days for mild lockdown compared to 480 days without TC2S. The epidemic’s time frame with and without TC2S in wards with more than three infected persons is 65 and 124 days respectively. Their simulations also found that a two-day work week (with stringent lockdown for the remaining five days) coupled with TC2S would reduce the number of deaths drastically — from 1,345 deaths per million to 34 deaths per million — and the epidemic’s duration from 675 days to 107 days. If introduced early enough, ward-level sealing and opening (WSO) may also help suppress the pandemic, provided all residents in hotspots can be tested. The model estimates WSO along with TC2S would reduce the duration of the epidemic from 115 days to 65 days, with the number of deaths coming down from 51 deaths per million to 18 deaths per million.
Dr Lancelot Pinto, a pulmonologist at PD Hinduja Hospital, who was not involved in the study, said, “The success of WSO depends on limiting movements across wards and this might be labour intensive and difficult to implement.” On the two-day work week option, Dr Pinto said the model must take into account the problem of overcrowding during periods when economic activities are allowed.
Vinay and Bhattacharyya’s paper was uploaded last week on medrxiv, a preprint server for health sciences, and has also been sent to the principal scientific advisor to the government of India, K Vijayraghavan.