Can the lockdown in England control new variant spread?

There is evidence that the earlier lockdown was generally effective in containing the spread of the previously predominant strain suggesting that the new variant grew in absolute terms. Controlling the spread of the new variant might be possible if the lockdown is stricter and compliance is better.

In a bid to slow down the spread of the highly transmissible new variant (VOC 202012/01) of SARS-CoV-2, the U.K. announced on Monday a fresh lockdown in London and southeast England; the lockdown is expected to last till mid-February. The decision to order a fresh lockdown comes after days of dithering; the scientific advisory panel had recommended days before Christmas that the government consider a national lockdown, including shutting down educational institutions.

As on December 4, U.K has reported 2.7 million cases and over 75,500 deaths, the second highest death toll in Europe. There have been more than 50,000 new SARS-CoV-2 cases reported daily since December 29, 2020 with a peak of nearly 59,000 cases on January 4, and over 400 deaths daily. On Monday, there were more than 26,000 COVID-19 patients admitted in hospitals, an increase of 30% from the previous week.

Though the new variant does not cause increased disease severity or mortality, a large surge in cases and resultant hospitalisation can lead to more deaths. The new variant is more transmissible, the reason why the reproduction number (number of people a person can infect) is 1.5-1.7; the spread is considered to be under control when the reproduction number is less than 1.

How the variant spread

Based on an analysis of cases and genome sequences of nearly 44,500 samples collected from England between September 21 and December 13, it was found that even during the previous lockdown, the new variant spread in a majority of locations. This even as fresh cases were generally dropping due to reduced spread of the then dominant strain.

There is evidence that the earlier lockdown was generally effective in containing the spread of the previously predominant strain suggesting that the new variant grew in absolute terms. The rapid spread of the new variant even during the previous lockdown might not reflect a general failure of virus control measures but highlights the inherent nature of the new variant to rapidly spread given its higher transmissibility.

Stricter lockdown

The fact that areas with slower baseline virus spread also reported slightly reduced spread of the new variant suggests that it is indeed possible to reduce if not suppress the transmission of the new variant if the lockdown is stricter and compliance is better. It is for this reason that unlike in the previous lockdown, schools and universities too have been ordered to be closed during the period of the current lockdown.

The new variant appears to affect a greater proportion of individuals aged under 20 years. The selective spread among the young might probably be more due to the fact that educational institutions were open during the previous lockdown than due to inherent nature of the variant to infect younger people.

Since a resurgence of the new variant is likely when the lockdown is lifted, the focus is on accelerating vaccine roll-out so that a sizeable percentage of the population is protected and the transmission chain is cut.

The rapid spread of the new variant should alert other countries, particularly where the variant has been found, to remain vigilant.

Published in The Hindu on January 6, 2021

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