New COVID-19 surges have lower excess mortality – But why, and will that last?

SARS-CoV-2 new case numbers are surging again in many countries (“2nd waves”), but with a notably lower death rate compared to the first wave. So is this the new norm? Well, as we have come to expect from COVID-19, the situation is complex and a lot of unknowns are at play. Achim Regenauer shares his insights.

The explanation for the lower death rate is still unclear and requires more analyses and monitoring. In the meantime, unsubstantiated explanations have arisen, including that what we now face is a milder variant of SARS-CoV-2 (as yet there is no evidence for this; a lengthy, severity-based comparative analysis between the new mutant and parent virus would be required).

In fact, there are many plausible explanations, and it’s highly probable that several are responsible¹:

• Higher numbers of infected younger people; the age profile is distinct from that of early 2020.
• Significantly more testing, particularly of younger people.
• More effective non-pharmaceutical interventions, such as the widespread use of facemasks and social distancing; reducing both transmission and severity of COVID-19.
• Improved protection of at-risk individuals, e.g. in nursing homes.
• The application of lessons learnt from the healthcare and case management of COVID-19 patients, e.g. more targeted use of ventilators and triage.
• The availability of more effective treatments for severe cases of COVID-19, e.g. Dexamethason and Remdesivir.

In my opinion it’s likely, for the reasons given above, that excess mortality will fundamentally remain lower than in early 2020, but that it will rise again, depending on the nature and timing of the following factors¹:

• There are reports of an extension in the duration between SARS-CoV-2 infection and death, in which case a surge in associated fatalities may follow in the short-term.
• If numbers escalate and ultimately overload healthcare systems, mortality could increase, especially for the elderly, in the medium term.
• The dramatic decline in the use of emergency services and reduced medical diagnosis and care provision during the early 2020 COVID-19 outbreak may cause increased mortality relating to non-COVID-19 diseases, such as cancers, heart attacks and stroke, in the long term².
• The prognosis for recovered COVID-19 patients is still unknown; future complications may lead to premature deaths in the long term.