On September 11, 2023, the U.S. Food and Drug Administration (FDA) gave the green light to Covid vaccines for 2023-2024, near the peak of SARS-CoV-2 transmission in the summer wave. This year, the warm season started earlier and, by some measures, is reaching much higher levels than in previous years.
Currently, wastewater detection of SARS-CoV-2 shows “very high” levels of the virus in 32 U.S. states and the District of Columbia. Another 11 states have “high” levels. Looking at trends, wastewater in southern and western parts of the country has levels of SARS-CoV-2 that are as high as those in the winters of 2022-2023 and 2023-2024, which peaked in late December.
Testing “positivity,” a metric that has weakened due to the dramatic decline in testsshows a weekly rate of 18.1% in mid-August; amid a testing volume of about 43,000. This rate, if it truly reflects cases, has not been seen since the initial omicron wave of January 2022, which peaked at 30.5%, with a testing volume of about 991,000.
The good news is that, due to the protection accumulated through previous infections and vaccinations, the two most serious parameters, emergency visits and deaths, have not registered increases. The weekly percentage of emergency visits with a diagnosis of Covid-19 is low and similar to that of the summer wave last year. Deaths are also minimal, although these are only provisional counts for the last few weeks.
Provisional percentage of COVID-19 deaths from emergency department (ED) visits diagnosed with COVID-19 by week in the U.S. Data reported by the Centers for Disease Control and Prevention (CDC).
The FDA has opted to offer annual Covid-19 vaccines in the lead-up to winter waves, not summer ones. The agency’s long-held idea has been to encourage Americans to get vaccinated against flu and Covid-19 at the same time between September and November, just before a surge of cold-weather respiratory illnesses hits. The new vaccination push may dampen levels of severe illness at a time when health care systems are most at risk of being overwhelmed.
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New reports suggest the virus can break out at any time of year, not just during the winter season.
Seasonality of covid-19
While seasonal flu and some other respiratory viruses reliably emerge almost exclusively in winter, Covid-19 seasonality was never a given. And, until now, summer waves have emerged with the same regularity as winter ones, creating some uncertainty for vaccine rollouts.
Some experts have recommended getting vaccinated against Covid-19 to protect against hot temperatures. “It is time to get a dose with this summer wave,” he told reporters on Sunday. CNN Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
However, the current vaccines target last year’s strains related to the XBB.1.5 omicron variant, which have long since disappeared and may not offer strong protection against the new KP.2 and KP.3 omicron variants. Even if the 2024-2025 KP.2-targeting vaccine were approved by the FDA this week and hit pharmacies next week, however, it would take two weeks for one dose to produce full protection. By then, the summer surge will likely have subsided. In fact, it appears to have already peaked in some parts of the country, including parts of the South and West.
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This case contradicts widespread concerns about booster shots of COVID-19 vaccines due to potential side effects, but the authors do not recommend over-vaccination.
Get vaccinated at the right time
The other consideration is timing to get the most protection from the likely winter surge. For healthy people ages 5 and older, the Centers for Disease Control and Prevention (CDC) recommended getting a single vaccine last year. Vaccines provide maximum protection for about four months. If you get your annual shot in early September, your protection may wane if Covid-19 peaks again later in the year, as it has for the past two years.
According to the 2023-2024 guidelines, people over 65 can receive a second booster dose of Covid-19 four months after receiving the first. People with moderate or severe immunosuppression can also receive additional doses of the updated Covid-19 vaccine.
Article originally published in Ars Technica. Adapted by Alondra Flores.
