By Mark Van Sumeren
April 11, 2022 – Covid waves have followed a standard template over the past few years: An outbreak hits Europe early, then reaches the United States within three to four weeks. The eruption here starts in the Northeast before spreading across the country.
This pattern appears to be holding with the BA.2 subvariant currently in circulation. Can this pattern provide any clues about what to expect from the BA.2 wave?
In early March, BA.2 infections struck Europe, especially Austria, France, Germany, and the Netherlands. Gratefully, infection rates subsequently ebbed this month. In each case, peak infection rates fell far short of the peaks recorded during the BA.1 surge.
Now, Northeastern states find themselves immersed in a BA.2 infection spread. Indeed, the highest new infection rates in the United States last week occurred in Vermont, Rhode Island, New York, and Massachusetts. Long a bellwether for Covid infection trends in the United States, New York witnessed a doubling in daily cases in less than three weeks. Nationwide, infections rose 6% last week, ending a pattern of declining rates since mid-January.
New York’s bellwether status provides clues about how this BA.2 wave might affect the rest of the country. Compared to each of the three most recent waves, this wave launched from a substantially lower rate (5x) than the BA.1 wave but at a higher rate than the summer 2021 and Fall 2020 waves. Hearteningly, infections grew more slowly in the first three weeks of this current wave than the BA.1 and summer 2020 waves and comparable to Fall 2020.
Slower increases, however, led to more prolonged surges during these earlier waves.
New York’s hospitalization experience sheds additional light on the possible severity of the BA.2 wave. Like with new cases, admissions with Covid started substantially lower with the BA.2 wave than with BA.1 and were comparable with the Summer 2021 and Fall 2020 waves. However, these admissions increased more slowly thus far with BA.2 than during any of these three earlier waves. From this prior experience, admissions will likely rise in New York in the short term.
So, New York’s experience, combined with Europe’s, suggests that BA.2’s impact could be relatively mild and with limited impact on healthcare resources. These experiences, however, provide a clouded view of how long the wave could last.
Do the experts concur?
The Institute for Health Metrics and Evaluation (IHME) maintains perhaps the most widely cited Covid model available. IHME’s latest model, released late last week, encourages an optimistic view. IHME predicts Covid infections in the United States will drop in half in the next month and by 80% by August 1. Admissions and patient days follow a similar pattern.
In summary, parts of the United States could experience an upswing in Covid cases in the next several weeks. However, the overall infection rate may remain relatively low, and the impact on hospital resources could be limited. This pattern could hold well into the summer months. However, we remain vigilant of what the Fall could bring to us, as the most significant surges in this country occurred when the weather turned colder.