Question: What fresh hell is this?! Vietnam fights new COVID-19 strain with higher infection rate

Answer: For those of you who haven’t read recent news out of Vietnam, here’s a synopsis — after months of successfully containing the virus, Vietnam is in the midst of an outbreak that local researchers (e.g. CDC-Vietnam) and officials (e.g. Health Minister) believe is the result of a more virulent strain that has also recently been seen in Bangladesh, UK, and Ireland. So what do we know?

Mutations and Virulence/Severity

While it is relatively easy to recognize viral mutations, it is difficult to understand how they impact virulence and disease severity. We know, for example, that the viral genome has become dominated over time by a one-base mutation strain (G strain) (Figure 1). And thanks to this lab-based study published in early July in Cell, we now have evidence to suggest that the G strain is more virulent than the original D strain. Important note: evidence from this study does not support the notion that the G strain causes more severe outcomes. The strain identified in Vietnam is yet another genetic variant. We need more data — and we need to see the data Vietnam is using to make these determinations — in order to understand how this new mutation impacts virulence and severity.

More Background

On 29 July, Reuters reported that “Prime Minister Nguyen Xuan Phuc said the current wave of infections was different to a second wave Vietnam fought in March…” and on 2 August, Reuters reported that “Health Minister Nguyen Thanh Long said the strain of the virus detected in the new outbreak is a more contagious one… each infected person may infect about 5–6 people compared to 1.8–2.2 people in the previous period.” Vietnam has submitted the genetic code to the GISAID database for further study. Meanwhile, WHO/Vietnam pushed back on the Vietnamese government’s assessment, stating “Based on what is known now, the contagion of the virus and the severity of the disease it causes have not changed. There is no evidence that the mutations observed so far have led to an increase or decrease in the virulence or severity of the disease.” Finally, for some basic background on viral mutations, see our Q&A of 3/25 (#mutations) and more recently, this news report from mid-July published in Science.

Figure 1. Changing Genome (from Science)