This was essential

Question

What does "this" refer to? Does "this" refer to the measure or the behavior or the step of instituting lockdowns?

In the initial phase of the pandemic, many countries instituted lockdowns (general population restrictions, including orders to stay at home and work from home) to slow the rapid spread of the virus. This was essential to reduce mortality, prevent health-care services from being overwhelmed, and buy time to set up pandemic response systems to suppress transmission following lockdown. Although lockdowns have been disruptive, substantially affecting mental and physical health, and harming the economy, these effects have often been worse in countries that were not able to use the time during and after lockdown to establish effective pandemic control systems. In the absence of adequate provisions to manage the pandemic and its societal impacts, these countries have faced continuing restrictions.

Source: The Lancet

Answer 1

I doubt that the author had any conscious idea whether “this” referred to the action (“lockdown”) or presumed effect (“slowing the spread”). I doubt it makes any real difference to meaning when the focus of the thought is the ultimate result of preventing overloading of hospitals, etc.

A leads to B leads to C leads to D leads to E. If what is important is E, each link in the whole casual chain from A through D is essential.

Answer 2

In this context, "this" refers to slowing the spread.

The lockdowns were intended to slow the spread; slowing the spread was essential to preventing health services from being overwhelmed.