Fourth Covid-19 'wavelet' in US hinges on continued spread of B117 variant

The Covid-19 pandemic in the US appears to be in its final stages, but a fourth "wavelet" in the near-term was still a possibility, analysts at Pantheon Macroeconomics said.

Key to the answer was whether the spread of the novel coronavirus strain first detected in the UK, known as B.1.1.7., would accelerate.

"We just don't know if the spread of B117 will accelerate, driving a sustained increase in national cases," they said.

On the flip-side, vaccinations were for sure accelerating and warmer weather in the top half of the Continental US were "powerful" forces as well.

Nevertheless, they remained "firmly" of the view that vaccinations would eventually beat the B.1.1.7 variant, which now accounted for over half of US cases, but it was possible that it could still pull ahead in the race against vaccinations - even if only briefly.

Furthermore, because a high proportion of the most vulnerable had now been vaccinated, they said that any increases in hospitalisations and deaths "would be much smaller than in previous waves".

Against that backdrop, the number of new Covid-19 cases in the US was still falling, but at a much slower pace.

Over the week ending on 18 March, the number of infections fell by 4% from the prior seven-day stretch and the seven-day average had decreased by just 1.9%.

Before the winter storm hit in February, which distorted the date but did not increase transmission, infections had been falling at a clip of 23%.

In Michigan state, B.1.1.7 was thus now clearly 'winning', sending the case count up by 150% over the past month and hospitalisations were rising.

New Jersey seemed to be heading in the same direction now, with cases having jumped by 30% from their February lows.

Cases were also creeping higher in Connecticut, Maine, Minnesota, Missouri, West Virginia and possibly in Pennsylvania.