Commentary: Why places with tighter restrictions have been hit worse by BA.2 Omicron sub-variant

ZERO CASES NOW MEANS DELAYED CASES LATER?

Long before COVID-19, it was known that non-pharmaceutical control measures, whether within a country or at its border, rarely stop a pandemic from spreading. Usually, these things – lockdowns, quarantines and so on – only delay a disease’s spread.

However, this may be sufficient to flatten the curve of infections and ease pressure on health services or to reduce illness and death by delaying most infections until treatments have improved and vaccines become available.

In reality, the most influential disease control factor is immunity, which can be generated by infection or vaccination. Both are important: The end of the pandemic in any country will likely depend on the proportion of people who have already had a COVID-19 infection and not just the proportion vaccinated.

Breakthrough infections in those who are vaccinated will drive their immunity to a higher level, while in the unvaccinated, an infection provides a level of protection that would otherwise have been absent. In fact, immunity following an infection now gives better protection against being infected in the future than immunity from a booster vaccine, especially once 90 days have passed since being vaccinated.