By Mark Van Sumeren
April 18, 2022 – Scientists found BA.2 circulating in the United States as early as last December. The subvariant’s subsequent rise coincided with an extended period of declining infections, leaving it with diminishing competition. Believed to be highly transmissible compared to its predecessors, BA.2 became the dominant strain in this country by late March. It now represents virtually all new cases here.
Despite its advantages, BA.2 has spread slowly and with few severe consequences thus far. Evidence from New York state suggests that vaccinations deliver strong protection against BA.2 infections, especially severe ones. Shall our fortune continue, could we see BA.2 recede year without extensive damage, like its track in Europe?
Last week, reported cases in the United States grew 14% from a week earlier. Friday marked the twelfth consecutive day during which the average weekly case rate rose from the prior week. To be sure, the current trend in week-to-week changes in new cases launched in early February. Before then, cases were declining each week at an accelerating rate. Since then, cases at first declined at a decelerating rate and subsequently at an increasing rate.
At first, BA.2’s spread through the Northeast. Massachusetts, New Jersey, and New York have experienced rising new daily cases for a month now, doubling in that time in Massachusetts, tripling in New Jersey, and more than tripling in New York. By last week, six Northeastern states, Connecticut, Massachusetts, New Jersey, New York, Rhode Island, and Vermont, recorded new case rates per capita among the highest in the country.
As of last week, BA.2’s impact stretched across the country. Thirty-four states witnessed more new cases last week than a week earlier. In Nebraska, new cases doubled in a week. In Alaska, Iowa, Kansas, and Tennessee, cases surged 60 to 70% higher. Delaware, Massachusetts, Maine, and New Hampshire recorded 50% more cases last week than a week earlier.
BA.2’s spread has spared our health care system thus far. While slightly more Covid patients were admitted to hospitals last week than the prior week, this admission rate remains lower than any other week during the pandemic. Covid patient days reached the lowest level ever seen during the pandemic.
At this point, no state requires more than 10% of inpatient beds to care for Covid patients. Only Maine, New York, and Vermont deploy more than one in twenty beds for these patients. To be fair, hospital admissions to Northeastern hospitals increased last week. Still, this census remains lower than current and historical levels.
Information reported by New York state provides clues to the role vaccinations play in keeping severe infections at bay. During the current BA.2 infection surge, vaccine effectiveness in preventing infections waned somewhat but remained near 70%. Infection rates surged among un- (and under-) vaccinated individuals but remained low among vaccinated persons.
According to these data, vaccine effectiveness in preventing hospitalizations increased to nearly 90% during the BA.2 surge in New York. Like with infections, hospitalization rates grew among the unvaccinated and remained steady for vaccinated people.
The Centers for Disease Control and Prevention rates most of the country at relatively low risk for infection and hospitalization. Using its Community Transmission rating system, the CDC rated two-thirds of communities nationwide as Low or Moderate for virus transmission. Ninety-four percent of U.S. communities earned a Low Community Level rating, reflecting the combined impact of virus transmission and hospitalization rates.
Globally, Covid cases fell 21% last week. Most large countries (84%) reported fewer cases last week than a week earlier. Those that reported higher cases benefited from already low cases per capita.
The highest rates among these large countries exist in South Korea, France, Australia, Germany, Austria, and Italy. However, case rates are dropping in these countries, particularly in hard-hit South Korea and Austria.
Experts now predict cases in the United States will rise slightly in this country for another two weeks and resume falling in early May. These same experts expect deaths with Covid to continue falling through early May.