San Francisco is being hit with high levels of several illnesses, including the nasty stomach bug norovirus, Covid and RSV, according to an analysis of city sewage by WastewaterSCAN.
Although San Francisco Covid levels are dropping as 2024 kicks off, around Christmas, part of San Francisco saw the highest Covid levels since data collection began roughly a year and a half ago.
Influenza virus levels remain low but continue to tick up, as the city announced Monday that its first flu death of the season happened last week.
Norovirus
Norovirus levels in San Francisco have surged, peaking around New Year's Eve and remaining high as levels slowly drop.
At the city's Oceanside wastewater plant, which recycles wastewater for San Francisco's western neighborhoods, levels started to spike after Dec. 19 until peaking on Dec. 29 and Dec. 31 before starting to decline, although levels on Jan. 7 remain elevated compared with levels before Christmas Eve.
Norovirus levels at the Southeast plant, which recycles wastewater for San Francisco's eastern neighborhoods, are starting to drop after a surge between Dec. 17 and Dec. 29, although levels are still high compared with levels during early and mid-December.
On Sunday, norovirus levels were up by 114% at the Oceanside plant and 58% at the Southeast plant compared with the same date one month ago.
Flu
Influenza levels in San Francisco are on the uptick but are drastically lower than they were during the 2022-2023 flu season.
Despite flu levels being much lower this season, the first flu death in the city claimed the life of an adult under the age of 65 who was not vaccinated and had preexisting medical conditions, the Department of Public Health said.
During this flu season, which the Centers for Disease Control and Prevention says typically spans between December and February, influenza levels at the city's Oceanside plant began to surge on Nov. 1 before dipping after Thanksgiving and spiking again after Christmas. Virus levels dropped after Dec. 27 but have begun to creep back up since Jan. 5.
At the city's Southeast plant, influenza levels followed a similar trend, beginning to increase on Nov. 8 and peaking on Nov. 26 before dropping in mid-December. Virus levels spiked again after Dec. 13 and peaked even higher on Dec. 22 and began dropping the next day. As of Monday, virus levels at the Southeast plant are dropping and remain below the December low.
Covid
Covid is trending down from a peak roughly a week ago as the city exits the holiday season.
Despite the downward trend in San Francisco, part of the city is seeing the highest levels of Covid infections since wastewater data collection began in mid-2022.
Wastewater from the city's Southeast treatment plant had the highest wastewater Covid virus levels on Dec. 25 since records began in May 2022, according to WastewaterSCAN.
At the Oceanside plant, Covid levels have fluctuated but remained high between Dec. 18 and Sunday, the latest available data. Overall, levels appear to be roughly double what they were during the same period a month prior spanning November and December.
At the city's Southeast plant, Covid levels aggressively spiked starting Dec. 19 before peaking on Christmas Day and have steadily declined since. Covid levels at that plant as of Sunday are roughly the same as during the Nov. 30 peak after Thanksgiving.
RSV
As of Sunday, RSV levels are 64% higher at the city's Oceanside plant than on Dec. 7. Over the same period at the Southeast plant, RSV levels were up 82%.
RSV is rising, with levels at San Francisco's Oceanside wastewater plant steadily ticking up beginning Dec. 20, although levels had been elevated but flat throughout early to mid-December.
At the city's Oceanside wastewater treatment plant, RSV levels started to tick up after Dec. 20, with the trend accelerating after Dec. 26. RSV levels surpassed the post-Thanksgiving surge on Jan. 3 and peaked the following day before dropping slightly.
At the city's Southeast plant, RSV levels were elevated compared with the first half of November but remained mostly flat until levels increased after Dec. 31, rising 107% between Dec. 31 and Sunday.
Amid the rise in viral levels, the San Francisco Department of Public Health is advising the public to stay up-to-date on severe flu, Covid and RSV vaccinations and information.
The health department also recommends people stay home if they feel sick and to get tested for Covid. You can get up to eight free Covid tests mailed to your household through a government program.