Clinical symptoms of SARS-CoV-2 breakthrough infection during the Omicron period in relation to baseline immune status and booster vaccination-A prospective multicentre cohort of health professionals (SURPRISE study)

Abstract

The effects of different types of pre-existing immunity on the frequency of clinical symptoms caused by the SARS-CoV-2 breakthrough infection were prospectively assessed in healthcare workers during the Omicron period. Among 518 participants, hybrid immunity was associated with symptom reduction for dizziness, muscle or limb pain and headache as compared to vaccination only. Moreover, the frequencies of dizziness, cough and muscle or limb pain were lower in participants who had received a booster vaccine dose. Thus, hybrid immunity appeared to be superior in preventing specific symptoms during breakthrough infection compared to vaccination alone. A booster vaccine dose conferred additional symptom reduction.

Keywords: Covid‐19; breakthrough infection; health professionals; symptoms; vaccine.

FIGURE 1

Symptoms of breakthrough infections during the Omicron period according to immune status and booster vaccination. Adjusted odds ratios (aOR) for symptoms during breakthrough infections in subjects with (A) hybrid immunity (group H) in comparison to those with vaccination (group V) only and (B) for the effect of a booster vaccine dose at least 7 days before infection during the Omicron period. Symptoms are sorted in order of increasing aOR for groups. Vertical lines (aOR = 1) indicate an absence of effect. OR shown in (A) and (B) are based on the same multivariable model and therefore adjusted for the respective other factors as well as age, sex, obesity (BMI > 30 kg/m²), any comorbidity and time from pre‐immunisation (i.e., either vaccination or infection prior to breakthrough infection) to breakthrough infection, which differed between those with and without booster (median 10.6 vs. 7.2 months).