COVID boosters restored antibody levels in nursing home residents, staff
SARS-CoV-2 antibodies fell over time after vaccination or COVID-19 infection but were restored with booster doses in West Virginia nursing home residents and staff, and antibody levels were significantly lower during the Delta than the Omicron variant surges in those with breakthrough infections, finds a study published yesterday in JAMA Network Open.
A team led by West Virginia University researchers obtained blood samples from 1,086 vaccinated residents and 1,053 vaccinated employees at 41 West Virginia nursing homes from Sep 13 to Nov 30, 2021, a period that spanned both Delta and Omicron predominance.
Age range was 18 to 103 years, 78% were women, 96% were White, and all had received either two doses of the Pfizer/BioNTech or Moderna COVID-19 vaccines or one dose of the Johnson & Johnson version.
Thirty-four percent of residents and 22% of staff reported previous COVID-19 infections, and 6% of residents and 5% of staff reported previous vaccine-breakthrough infections, 82% of which occurred during Delta, from August to October 2021. Ten percent of the total cohort had breakthrough infections from Jan 22, 2021, to Jan 16, 2022, with 90% occurring from August 2021 to January 2022.
A total of 101 participants had breakthrough infections from October 2021 to January 2022, of whom 44% had received a booster dose before infection. Sixty-five infections occurred amid Omicron in January 2022; of them, 54% occurred in residents, 69% of whom had received a booster, compared with 3% of staff, 37% of whom were booster recipients.
Antibody levels fell over time after vaccination or infection but rebounded after a booster dose, with a particularly strong response in those previously infected. Antibody concentrations were significantly lower among vaccinated participants who subsequently tested positive for COVID-19 during Delta, but there was no difference between antibody level and infection rates during Omicron.
The authors said that although the findings are inconclusive in providing an antibody correlate of protection against infection, they “suggest that among nursing home residents, COVID-19 vaccine boosters are important.”
Sep 13 JAMA Netw Open study
WHO adds US to countries with circulating polio
The World Health Organization (WHO) has added the United States to the list of countries where circulating vaccine-derived poliovirus type 2 (cVDPV) has been detected, based on case and environmental detections in and around New York City.
According to the Centers for Disease Control and Prevention (CDC), the United States met the criteria because of several detections in wastewater and a case of paralytic polio in an unvaccinated adult in Rockland County, New York, detected last month.
“These two things—one individual with VDPV and at least one detection of a related VDPV in an environmental sample—meet WHO’s definition of cVDPV, and CDC submitted this data to WHO for inclusion on its list of countries with cVDPV,” the CDC said in a media statement.
The United States is now on a list with 30 other countries with cVDPV. According to the CDC, cVDPV occurs when local immunity to poliovirus is low enough to allow prolonged transmission of the original weakened virus in the oral polio vaccine.
In other polio news, the WHO has posted a notice about the first cVDPV case in Algeria. The WHO was notified of a case of cVDPV2 with acute flaccid paralysis from Tamanrasset province, southern Algeria. The patient is a child under the age of 2 who had not been vaccinated against polio nor traveled outside of Tamanrasset. This is the first cVDPV2 case identified in Algeria.
Sep 13 CDC media statement
Sep 13 WHO Algeria notice
USDA APHIS describes 26 more H5N1 avian flu detections in wild birds
The US Department of Agriculture Animal and Plant Health Inspection Service (APHIS) has added reports of 36 more H5N1 avian flu detections in wild birds, raising the total to 2,276.
They are from a range of locations, including Florida, New York, Wisconsin, Utah, and Nevada, with most detections in black vultures and waterfowl.
Florida has the most detections, with 255, followed by North Dakota with 248 and North Carolina with 143.
Highly pathogenic avian flu has now also been detected in commercial poultry in Belize, the southernmost detection of H5 influenza in the Americas. The poultry were found in the Blue Creek Community, Orange Walk District. The farm was depopulated immediately, according to the Belize Agricultural Health Authority, and the pathogenicity and subtype have not yet been determined.
Sep 14 USDA APHIS update
Sep 13 Belize Agricultural Health Authority notice