Timely COVID-19 boosters can prevent care facility outbreaks

Coronavirus disease 2019 (COVID-19), caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can cause severe illness in the elderly and in patients with certain co-morbidities. It often happens.

Long-term care facilities (LTCFs) often had higher COVID-19 mortality rates than the rest of the population during most of the pandemic. This gave priority to LTCF residents during vaccine rollout. However, there are few data on vaccine efficacy (VE) in this group.

study: COVID-19 Outbreak in Aged Care Homes: Very Low Vaccine Effectiveness and Slow Impact of Booster Vaccination CampaignsImage credit: Suwin / Shutterstock.com

new vaccination This study investigates an outbreak of the SARS-CoV-2 Delta variant in the Dutch LTCF. It continued to infect individuals and cause severe illness even after containment measures were put in place and vaccine booster campaigns were launched. The aim of this study was to assess primary VE against COVID-19 infection and mortality, with a particular focus on booster vaccine efficacy.

prologue

Elderly residents of LTCF are at increased risk of COVID-19 due to communal living spaces that facilitate transmission of SARS-CoV-2, weakened immune systems, and comorbidities such as dementia, heart disease, and chronic lung disease. higher. An LTCF resident is rarely brought to a regional testing center for her COVID-19 screening and is not frequently hospitalized.

Residents of LTCF were given priority for vaccination, but previous studies reported that immunity declined rapidly from 12 weeks after vaccination. The lack of data on her subsequent VE makes it difficult to devise appropriate booster dose guidelines in this patient population.

Current studies report occurrences of LTCF in both staff and residents. The Dutch facility had two physical wards and two wards for psychiatric and/or extremely elderly patients. These four wards have 63 residents.

Additionally, 88 residents lived in three semi-detached housing units. These residents had access to the same nursery and restaurant rooms as the wards, and most of her 42 residents at one of these facilities participated in these activities.

This left residents in two other housing complexes, but staff and individual housing facilities were relatively isolated from the communal facilities. In total, there were a total of 160 staff working and a total of 151 residents working during the outbreak.

The first COVID-19 case occurred in one of the psychiatric wards of a fully vaccinated patient after contact with an infected individual. Testing was then performed on patients and staff on all wards and on close contacts both immediately and on day 5 after the last exposure.

All infected residents were quarantined for 24 hours from onset or until symptom-free for at least 7 days, and other residents were using personal protective equipment (PPE).no visitors COVID-19 symptoms Wearing a face mask was compulsory.

Following initial ward-level patient isolation, entire wards, including staff and patients, were quarantined as the outbreak expanded. This was followed by further cases outside the ward, including staff. These workers and the ward they are currently working on were also quarantined.

At this point, visits were prohibited, common areas were closed, and other daily activities were restricted. On December 6, 2021, all ward patients and a number of patients in adjacent complexes who were still negative for COVID-19 received a booster vaccine.

New COVID-19 cases occurred in all LTCF wards and housing complexes with social interaction with LTCF. Testing and separate isolation measures were in place and all common areas were closed.

The outbreak, which began on 20 November 2021, was finally contained when the last patient was released from isolation on 22 December 2021.

Survey results

The ward and affected housing complex consisted of 105 residents, with a median age of 85 years and two-thirds female. Thirteen had a history of COVID-19, eight had not been vaccinated, but all other residents were fully vaccinated, with the last vaccination on July 6, 2021. has been done before. The current outbreak received a booster dose in December.

A total of 70 cases were reported among LTCF residents, with an overall attack rate (AR) of 67%. The first affected ward had a much higher AR of 94%, followed by him on one somatic ward with 80%. The AR of the affected residential complexes was 62%.

All COVID-19 cases were caused by SARS-CoV-2 Delta variants. His VE on primary vaccination against this strain was 17%, with 70% mortality within 30 days. Interestingly, this was unaffected by his previous history of COVID-19. This is probably due to the small number of only 13 of his 105 previously infected patients.

Among unvaccinated patients, lethality 33% compared with 12% of fully vaccinated residents. Few cases were reported from six days after his booster dose. Boosted patient he did not die of COVID-19.

implication

The high infection rate in the fully vaccinated population despite isolation and containment measures adds to current knowledge about the limitations of primary vaccination. The second vaccination occurred more than 6 months before his occurrence in this study.

Full vaccination provided 17% protection against infection. However, he had a 70% reduction in mortality compared to those who were not vaccinated. Thus, he died in 1/3 of the unvaccinated cases compared to 12% of the fully vaccinated cases.

High AR in the vaccinated subgroup may be due to repeated exposures, exposure to high viral loads, or novel SARS-CoV-2 variants that evaded vaccine-induced immunity. Consistently higher than community AR, probably due to increased exposure. This may explain our current findings within LTCF’s self-contained environment.

In fact, of 30 residents who remained susceptible to SARS-CoV-2 but received a booster dose, only 5 had cases. Each of these occurred two weeks after he received the booster dose. No cases were reported during the third week.

Researchers believe a timely booster dose helped stop the outbreak. Nonetheless, her one-third of the boosted patients had already had hybrid immunity before he had a history of COVID-19.

[These findings] Highlighting the vulnerability of adults living in LTCF and the need for timely booster vaccinations”

Booster vaccine doses appear to be effective only for 7 or more days from the date of administration in this population group. Once activated, the resulting immunity may prevent further transmission of SARS-CoV-2.

The small sample size of the current study indicates the need for large-scale studies in the future to validate these inferences.