Although this year’s heat wave appears to be milder than that seen during the pandemic emergency, Covid-19 is on the rise for the fourth consecutive summer.
Indicators such as Covid-19 hospital admissions, emergency services, positive test results and wastewater discharges have all risen over the past month, according to CDC monitoring data, but no significant recovery is yet in sight. Disease Control and Prevention (CDC). From June 10 to July 29, positive cases rose from 4.1% to 8.9%. For reference, as of December 31, 2022, the test positivity rate for the most recent winter wave was 10.6%.
Coronavirus cases increase during summer
On the bright side, however, weekly U.S. hospital admissions and deaths from the virus remain at their lowest since the pandemic began. At present, the death toll does not indicate an increase, although there has been a delay in the reporting of information. New hospital admissions rose only slightly, with about 8,000 in the week of July 22, up from about 6,300 in the week of June 24.
Available data puts the death toll at between 500 and 400 in recent weeks. The CDC data no longer show excess deaths, or numbers above expected baseline levels. That said, the current weekly number of deaths from all causes in the U.S. matches the expected number of deaths before the pandemic.
This seemingly mild wave may have been caused by a variety of factors, including immunity to previous vaccines and infections, and the fact that many people who were susceptible to the virus died in previous waves. The cumulative death toll from the covid-19 pandemic in the United States has surpassed 1.1 million.
Even so, the virus has made another comeback this summer, raising the question of whether the summer wave will be a regular seasonal cycle. Many health experts believe that SARS-CoV-2 is primarily a cold-weather virus that, like other respiratory bacteria such as the common cold and flu, proliferates in the fall and winter. For example, the U.S. Food and Drug Administration (FDA) has developed a covid-19 vaccine booster program based on the annual flu shot schedule.
But the seasonality of SARS-CoV-2 remains unclear, and researchers don’t know exactly what causes the summer wave, which typically begins in the southern United States. One of the main assumptions is that the economic upturn coincides with the season of holidays, travel and meetings.
New coronavirus variant: EG.5.1
Another potential wave factor is emerging variants. Currently, a new sub-variant of omicron, E.G.5Nicknamed “Eris”, associated with XBB.1.9.2, it is gaining strength in the US, UK, and parts of Asia against the so far dominant variants XBB.1.5 and XBB.1.16. However, surveillance of SARS-CoV-2 variants has declined so much that the CDC only has enough data to estimate the prevalence of variants in three of the 10 U.S. health regions (California, New York, and the Southeast region) Condition.
A descendant of the world’s most prevalent coronavirus strain, the omicron, the EG.5 subvariant is spreading rapidly and accounts for 1 in 7 cases of Covid-19 in the UK, as recently reported by UK health authorities such as HSA . that country.
According to the information Washington post Stuart Turville, an associate professor at the University of New South Wales in Sydney, a virologist and researcher, believes that while the EG. General and Although it is more contagious, it’s not more aggressive“The effect on the human body is almost the same,” added Prof. K. Srinath Reddy of the Public Health Foundation of India.
Finally, according to an FDA advisory committee meeting in June, vaccine makers may release an updated covid-19 booster this fall, targeting the XBB subvariant lineage, possibly XBB.1.5.
Article originally published on Ars Technica. Adapted by Andrea Osornio.