Two thirds of nursing home residents and staff in England were infected with SARS-CoV-2 in the first 2 years of the pandemic, suggests an observational study to be presented at the April 15 to 18 European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Copenhagen, Denmark.

University College London researchers used antibody blood testing to estimate the percentage of nursing home residents and employees who had COVID-19 from March 2020 to March 2022. Their data came from the ongoing VIVALDI study, which has been tracking infections and immunity to SARS-CoV-2 in English nursing homes since the pandemic began.

Participants included 1,794 nursing home residents with an average age of 87 years and 3,385 workers with an average age of 47 years tested for antibodies at least once in 220 facilities.

Ongoing surveillance of infection and immunity in these settings is important.

Despite making up less than 1% of the population in England, nursing home residents accounted for roughly a third of all COVID-related deaths over the study period, but the researchers noted that the true percentage of infections is unknown because polymerase chain reaction (PCR) testing—the gold standard—was limited, meaning that most infections in the early months of the pandemic were not documented.

Higher infection rate among residents

During the study period, 998 residents and 1,782 staff tested positive for SARS-CoV-2 antibodies at least once, suggesting previous infection. The rate of infection was significantly higher among residents, at 0.13 cases per 100 person-days, than among staff, at 0.11 per 100 person-days.

The average time at risk in the whole group was 547 days (439 days for residents and 610 days for workers). The cumulative risk of infection in the entire group was 65%.

Lead author Maria Krutikov, MD, said the predominance of previously infected residents, as well as vaccination, may explain a recent drop in COVID-19 deaths in English nursing homes. "Ongoing surveillance of infection and immunity in these settings is important for informing policy decisions around screening and revaccination as we learn to live with the pandemic," she said.

In an ongoing randomized trial investigating whether the transfer of gut microbiota from mother to baby can safely restore normal microbiota in babies after caesarian delivery, more than 40% of enrolled mothers tested positive for potentially harmful pathogens, Finnish researchers reported this week at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID).

The trial, which is being conducted at Helsinki University Hospital, is enrolling healthy pregnant women scheduled for C-section and randomizing their newborns to receive 3.5 milligrams of screened intestinal microbiota or placebo mixed in mother's milk. The infants are then followed for up to 24 months. The aim of the trial is to see whether the normal microbial colonization process that occurs in vaginally born infants, which is disrupted by C-section delivery, can be restored through postnatal oral transfer of the maternal fecal microbiome.

But among 90 mothers who've been recruited since 2019, all of whom were asymptomatic and had no recent history of antibiotic use or travel outside Europe, 38 (42%) tested positive for pathogens that could cause illness in newborns, including Heliobacter pylori, group B Streptococcus, and the parasite Deintamoeba fragilis.

This procedure should be only performed after careful screening for potential pathogens.

Screening also revealed the presence of methicillin-resistant Staphylococcus aureus, enterohemorrhagic Escherichia coli, and extended-spectrum beta-lactamase enzymes, which can confer resistance to multiple antibiotics.

"The high rate of significant pathogens found in healthy mothers underscores that this procedure should be only performed after careful screening for potential pathogens," lead investigator Otto Helve, MD, PhD, said in an ECCMID press release.

Helve said that 31 babies have received the transplant or placebo to date, without any noticeable side effects. Assessment of whether the transplant is enriching the microbiome will be begin in May.