BACKGROUND There were increased SARS-CoV2 hospitalizations and deaths noted during Omicron (B.1.1.529) variant surge in UK despite decreased cases, and the reasons are unclear.

METHODS In this observational study, we analyzed reported SARS-CoV2 cases, hospitalizations and deaths during the COVID-19 pandemic in the UK. We also analyzed variables that can affect the outcomes. The vaccine effectiveness among those ≥18 years of age (August 16, 2021 to March 27, 2022) was analyzed.

RESULTS Of the total cases (n= 22,072,550), hospitalizations (n=848,911) and deaths (n=175,070) due to COVID-19 in UK; 51.3% of cases (n=11,315,793), 28.8% of hospitalizations (n=244,708) and 16.4% of deaths (n=28,659) occurred during Omicron variant surge. When comparing the period of February 28-May 1, 2022 with the prior 12-weeks, we observed a significant increase in the case fatality rate (0.19% vs 0.41%; RR 2.11 [2.06-2.16], p<0.001) and odds of hospitalization (1.58% vs 3.72%; RR 2.36[2.34-2.38]; p<0.001). During the same period a significant increase in cases (23.7% vs 40.3%; RR1.70 [1.70-1.71]; p<0.001) among ≥50 years of age and hospitalizations (39.3% vs 50.3%;RR1.28 [1.27-1.30]; p<0.001) and deaths (67.89% vs 80.07%;RR1.18 [1.16-1.20]; p<0.001) among ≥75 years of age was observed. The vaccine effectiveness (VE) for the third dose was in negative since December 20, 2021, with a significantly increased proportion of SARS-CoV2 cases hospitalizations and deaths among the vaccinated; and a decreased proportion of cases, hospitalizations, and deaths among the unvaccinated. The pre-existing conditions were present in 95.6% of all COVID-19 deaths, various ethnic, deprivation score and vaccination rate disparities noted that can adversely affect hospitalization and deaths among compared groups.

CONCLUSIONS There is no discernable vaccine effectiveness among ≥18 years of age, vaccinated third dose population since the beginning of the Omicron variant surge. Pre-existing conditions, ethnicity, deprivation score, and vaccination rate disparities data need to be adjusted for evaluating VE for hospitalizations and deaths. The increased cases with significantly increased hospitalizations and deaths among the elderly population during the Omicron variant surge underscores the need to prevent infections in the elderly irrespective of vaccination status with uniform screening protocols and protective measures.

Source – https://www.medrxiv.org/content/10.1101/2022.06.28.22276926v1.full