The risk of hospitalization is higher in people infected with the alpha variant

Since its discovery in England in November 2020, the variant of SARS-CoV-2 now called alpha has been found in 135 countries around the world. Its prevalence increases rapidly in the territory of origin and becomes the predominant lineage in mid-December.

Now researchers in this country have concluded that the risk of hospitalization is higher for people infected with the alpha variant (B.1.1.7) compared to wild-type SARS-CoV-2, which probably reflects a more serious illness. The highest severity may be specific to adults over 30.

“The initial concerns with B.1.1.7 arose from analyzes which determined higher transmissibility. On December 18, 2020, the variant was redesignated as a disturbing variant and subsequent studies found it to be associated with higher mortality than other variants of SARS-CoV-2, ”the researchers described in a publication from BMJ.

The way in which COVID-19 overloads hospital services is known to be a key element in making progress in controlling the pandemic, a fact that influences decisions about preventive measures taken by countries. And although the prevalence of the alpha variant has recently declined in England, “B.1.1.7 is the predominant lineage in several countries, and any possible increase in the likelihood of hospital admission with this variant will affect the burden of national health in these countries. “, Observed the experts.

“More recently, an increased risk of ICU admission has been reported for proven COVID-19 patients in the community,” they analyzed. A study, based on whole genome sequencing, reported the risk of hospital admission by individual-level follow-up of COVID-19 patients due to variant B.1.1.7 compared to wild-type SARS-CoV-2”. However, this study was limited by a moderate sample size due to operational limitations of sequencing, which resulted in wide confidence intervals for the risk estimates. Hospital admissions linked to individual variant cases based on data from routine testing in England, providing a larger sample, have yet to be analyzed, leaving a void in the available evidence.

The genetic profile of the alpha variant includes a six-nucleotide deletion in the S gene and has been associated with target failures for this gene in polymerase chain reaction (PCR) tests using a three-gene test (ORF1ab, N -gen and S -gene). Although other mutations can also cause S target gene (SGTF) failure, it has been confirmed that over 90% of SGTF samples sequenced since the week of November 23, 2020 matched the UK mutation profile.

The objective of the study was to assess whether there is a causal relationship between infection with the alpha variant, compared to infection with the wild-type SARS-CoV-2 variants, and the risk of ‘hospitalization. A secondary goal was to re-estimate the risk of mortality for patients with this variant compared to wild-type variants that were reported in previous analyzes of the study dataset.

For analysis, patients with a positive PCR test for SARS-CoV-2 between November 23, 2020 and January 31, 2021 were included and whose sample had been analyzed in one of the Lighthouse laboratories of the TaqPath test. During the study period, 839,278 patients with confirmed SARS-CoV-2 infection and valid SGTF status were reported by TaqPath Lighthouse assay laboratories and were not admitted to hospital in the six weeks before testing positive: 592,409 patients with SGTF variants and 246,869 patients with non-SGTF variants.

These patients accounted for 41.0% of all confirmed cases during this period. The mean age of patients with SGTF variants was 37.6 years and the mean age in the group without SGTF was 37.8 years. There were marked differences by region, with a higher proportion of patients with SGTF variants in London, the East of England and the South East, as well as differences over time, the majority of cases of SGTF variants occurring towards the end of the year. December 2020 and early 2021, while cases without SGTF variants have declined over time.

Among the 592,409 patients with SGTF variants, 27,710 (4.7%) hospitalizations occurred within 1 to 14 days, compared with 8,523 (3.5%) among the 246,869 patients without SGTF variants. Only 911 (0.15%) patients with SGTF variants and 399 (0.16%) of those without SGTF variants died within 14 days without prior hospitalization; therefore, how the deaths were treated would make little difference in the risk ratio estimates for hospital admission.

In a secondary analysis, the aim of the study was to estimate the adjusted risk ratio of death within 28 days of testing positive for patients with SGTF compared to variants without SGTF. “We do this by tracking patients from the date of their first positive test until the date of death if they are deceased within 28 days or censoring them after 28 days. Because the result was rarer compared to hospital admission, we estimated the risk ratio based on Cox regression stratified by age, region of residence and week of sampling and including the main effects. for other possible confounding factors, ”the researchers said.

KEEP READING