Notes from the Field: Epidemiologic Characteristics of SARS-CoV-2 Recombinant Variant XBB.1.5 - New York City, November 1, 2022-January 4, 2023

Emergence and dissemination of SARS-CoV-2 XBB.1.5 in New York

The recombinant SARS-CoV-2 Omicron XBB.1.5 variant was first detected in New York City (NYC) and rapidly became the predominant variant in the area by early 2023. The increased occurrence of circulating variants within the SARS-CoV-2 XBB-sublineage prompted the modification of COVID-19 mRNA vaccines by Moderna and Pfizer-BioNTech. This update, implemented in mid-September 2023, involved the incorporation of a monovalent XBB.1.5 component. Considering that NYC probably played a central role in the emergence of the XBB.1.5 variant, we conducted phylogeographic analysis to investigate the emergence and spread of this variant in the metropolitan area. Our analysis confirms that XBB.1.5 emerged within or near the NYC area and indicates that XBB.1.5 had a diffusion velocity similar to that of the variant Alpha in the same study area. Additionally, the analysis of 2,392 genomes collected in the context of the genomic surveillance program at NYU Langone Health system showed that there was no increased proportion of XBB.1.5, relative to all cocirculating variants, in the boosted compared to unvaccinated individuals. This study provides a comprehensive description of the emergence and dissemination of XBB.1.5.

Association between the health vulnerability of family members and concern about the contagion of COVID-19 in Peruvian residents after the pandemic

Background

The COVID-19 pandemic has created additional challenges for family health. Worry, fear, and anxiety associated with this disease can affect the perception of family health. The study's objective was to analyze the factors associated with health vulnerability of family members in the Peruvian population after pandemic.

Methods

Observational, cross-sectional, and analytical study. Sampling was nonprobabilistic. The sample consisted of 519 residents who met the following inclusion criteria: Peruvian resident, of both genders, over 18 years of age, who lives with their family, and who agrees to participate in the study. For data collection, the "SALUFAM" and "PRE-COVID-19" scales were used, which measure the health vulnerability of family members and concern about the contagion of COVID-19, respectively. Data collection was done between January and March, 2023.

Results

Living in the Coast region increases by 3.299 times (95% CI = 1.55-9.28; p = 0.003) the probability of lower family health vulnerability compared to residents from the Jungle region. In the same way, having a low concern about the contagion of COVID-19 increases 2.77 times (95% CI = 1.02-7.53; p = 0.044) the probability of less vulnerability to family health, unlike participants who are highly concerned about the contagion of COVID-19.

Conclusions

It should be necessary to design prevention and family health promotion strategies according to the geographical region; it is also essential to provide education on the risks and the importance of prevention measures for COVID-19, regardless of their initial level of concern.

Vaccine effectiveness against hospitalisation estimated using a test-negative case-control study design, and comparative odds of hospital admission and severe outcomes with COVID-19 sub-lineages BQ.1, CH.1.1. and XBB.1.5 in England

Background

Since the first emergence of Omicron BA.1 in England in November 2021, numerous sub-lineages have evolved. In September 2022, BA.5 dominated. The prevalence of BQ.1 increased from October, while the prevalence of CH.1.1 and XBB.1.5 increased from December 2022 and January 2023, respectively. Little is known about the effectiveness of the vaccines against hospitalisation with these sub-lineages, nor the relative severity, so we here used national-level electronic health records from England to estimate vaccine effectiveness and variant severity.

Methods

The study period for tests contributing to all analyses was from 5th December 2022 to 2nd April 2023, when the variants of interest were co-circulating. A test-negative case-control study was used to estimate the incremental effectiveness of the bivalent BA.1 booster vaccines against hospitalisation, relative to those with waned immunity where the last dose was at least 6 months prior. The odds of hospital admission for those testing PCR positive on the day of an attendance to accident and emergency departments and the odds of intensive care unit admission or death amongst COVID-19 admissions were compared between variants. Additionally, a Cox proportional hazards survival regression was used to investigate length of stay amongst hospitalised cases by variant.

Findings

Our vaccine effectiveness study included 191,229 eligible tests with 1647 BQ.1 cases, 877 CH.1.1 cases, 1357 XBB.1.5 cases and 187,348 test negative controls. There was no difference in incremental vaccine effectiveness against hospitalisation with BQ.1, CH.1.1 or XBB.1.5, nor was there a difference in the severity of these variants. Effectiveness against hospitalisation was 48.0% (95% C.I.; 38.5-56.0%), 29.7% (95% C.I.; 7.5-46.6%) and 52.7% (95% C.I.; 24.6-70.4%) against BQ.1, CH.1.1 and XBB.1.5, respectively, at 5-9 weeks post booster vaccination. Compared to BQ.1, the odds of hospital admission were 0.87 (95% C.I.; 0.77-0.99) and 0.88 (95% C.I.; 0.75-1.02) for CH.1.1 and XBB.1.5 cases attending accident and emergency departments, respectively. There was no significant difference in the odds of admission to intensive care units or death for those with CH.1.1 (OR 0.96, 95% C.I.; 0.71-1.30) or XBB.1.5 (OR 0.67, 95% C.I.; 0.44-1.02) compared to BQ.1. There was also no significant difference in the length of hospital stay by variant.

Interpretation

Together, these results provide reassuring evidence that the bivalent BA.1 booster vaccines provide similar protection against hospitalisation with BQ.1, CH.1.1 and XBB.1.5, and that the emergent CH.1.1 and XBB.1.5 sub-lineages do not cause more severe disease than BQ.1.

Funding

None.

Genomic Surveillance for SARS-CoV-2 Variants: Circulation of Omicron Lineages - United States, January 2022-May 2023

CDC has used national genomic surveillance since December 2020 to monitor SARS-CoV-2 variants that have emerged throughout the COVID-19 pandemic, including the Omicron variant. This report summarizes U.S. trends in variant proportions from national genomic surveillance during January 2022-May 2023. During this period, the Omicron variant remained predominant, with various descendant lineages reaching national predominance (>50% prevalence). During the first half of 2022, BA.1.1 reached predominance by the week ending January 8, 2022, followed by BA.2 (March 26), BA.2.12.1 (May 14), and BA.5 (July 2); the predominance of each variant coincided with surges in COVID-19 cases. The latter half of 2022 was characterized by the circulation of sublineages of BA.2, BA.4, and BA.5 (e.g., BQ.1 and BQ.1.1), some of which independently acquired similar spike protein substitutions associated with immune evasion. By the end of January 2023, XBB.1.5 became predominant. As of May 13, 2023, the most common circulating lineages were XBB.1.5 (61.5%), XBB.1.9.1 (10.0%), and XBB.1.16 (9.4%); XBB.1.16 and XBB.1.16.1 (2.4%), containing the K478R substitution, and XBB.2.3 (3.2%), containing the P521S substitution, had the fastest doubling times at that point. Analytic methods for estimating variant proportions have been updated as the availability of sequencing specimens has declined. The continued evolution of Omicron lineages highlights the importance of genomic surveillance to monitor emerging variants and help guide vaccine development and use of therapeutics.