Investigating the association between COVID-19 vaccination and care home outbreak frequency and duration

OBJECTIVES

At the end of 2020, many countries commenced a vaccination programme against SARS-CoV-2. Public health authorities aim to prevent and interrupt outbreaks of infectious disease in social care settings. We aimed to investigate the association between the introduction of the vaccination programme and the frequency and duration of COVID-19 outbreaks in Northern Ireland (NI).

STUDY DESIGN

We undertook an ecological study using routinely available national data.

METHODS

We used Poisson regression to measure the relationship between the number of RT-PCR confirmed COVID-19 outbreaks in care homes, and as a measure of community COVID-19 prevalence, the Office for National Statistics COVID-19 Infection Survey estimated the number of people testing positive for COVID-19 in NI. We estimated the change in this relationship and estimated the expected number of care home outbreaks in the absence of the vaccination programme. A Cox proportional hazards model estimated the hazard ratio of a confirmed COVID-19 care home outbreak closure.

RESULTS

Care home outbreaks reduced by two-thirds compared to expected following the introduction of the vaccination programme, from a projected 1625 COVID-19 outbreaks (95% prediction interval 1553-1694) between 7 December 2020 and 28 October 2021 to an observed 501. We estimated an adjusted hazard ratio of 2.53 of the outbreak closure assuming a 21-day lag for immunity.

CONCLUSIONS

These findings describe the association of the vaccination with a reduction in outbreak frequency and duration across NI care homes. This indicates probable reduced harm and disruption from COVID-19 in social care settings following vaccination. Future research using individual level data from care home residents will be needed to investigate the effectiveness of the vaccines and the duration of their effects.

Octanol-Water Partition Coefficients of Surfactants: Slow Stirring/Surface Tension Method

A slow stirring method to measure log P values of water-soluble surfactants is described. Aqueous surfactant solution is equilibrated with octanol. A surface tension technique is used to determine the decrease in concentration in the aqueous phase. Interference from octanol, which is surface active, is prevented by evaporation and redissolution of the sample. For industrial surfactants this method gives a log P value that is effectively weighted according to the surface activity of the components. The test can be used to screen surfactants for a possible risk of bioaccumulation as it is generally accepted that substances with log P < 3 are unlikely to bioaccumulate. The apparent log P of an alkane sulfonate was 1.5 when a 1 g/L aqueous solution was equilibrated with an equal volume of octanol. Due to ion pair formation in the octanol phase the apparent log P decreased with concentration. As a result, the tendency to partition into octanol is likely to be less at environmentally relevant concentrations.

Effects of group discussion and guided patient care experience on nurses' attitudes towards care of patients with AIDS

Nurses with limited experience in caring for persons with AIDS (PWAs) were randomized into three groups receiving an educational session on universal precautions and (a) three group discussion sessions; (b) three sessions of caring for a PWA; or (c) assessment materials only. Both interventions were conducted by a nursing instructor experienced in care of PWAs and infectious diseases over a 3-4 week period. Measures included instruments for assessing prejudicial attitudes towards homosexual PWAs, self-ratings of infectious disease knowledge, ratings of perceived comfort and confidence in caring for PWAs, and a measure of willingness to provide care to PWAs. Results showed no significant change in willingness to provide care over time in any of the groups. Multiple regression exploring predictors of willingness to provide care found only the measure of AIDS prejudice to be an independent predictor of willingness to provide care to PWAs 6 months after completion of the intervention phase.

A cluster of cases of feline dysautonomia (Key-Gaskell syndrome) in a closed colony of cats

Twenty-five cases of feline dysautonomia (Key-Gaskell syndrome) occurred in a closed cat colony over a period of three weeks. The clinical and pathological signs were sufficiently similar to those reported during the 1982-1986 outbreak to establish a positive diagnosis. The special epidemiological and environmental circumstances of the outbreak provide a new insight into the cause(s) of the syndrome.