Autonomic Function Comparison Between Unvaccinated and Vaccinated Young Adults Infected with COVID-19: An Observational Study 4346

Abstract

Objectives

To compare heart rate variability (HRV) indexes between coronavirus disease 2019 (COVID-19) infected unvaccinated (UYA) and vaccinated young adults (VYA).

Design

Observational study evaluating differences in HRV between COVID-19 infected vaccinated and UYA.

Setting

General community of young adults infected with COVID-19 in São Paulo state, Brazil.

Participants

Twenty-three UYA and 10 VYA with mild to moderate clinical COVID-19 were evaluated. Eligibility criteria: men and women, 20-40 years. Recruitment was through the media and diagnosis was via polymerase chain reaction test. Mean age of UYA was 29.17±6.32 and 26.22±5.23 years for VYA. HRV indexes were measured via heart monitor (Polar RS800CX) and this took place in a quiet room maintained at room temperature following at least 24 hours of complete abstinence from exercise, alcohol, and caffeine intake. Participants were fitted with a chest strap for 25 minutes and HRV was performed on 256 consecutive intervals and of these the most stable tachogram was selected. The indexes are divided into time domain, frequency domain, and nonlinear variables. The major indexes of note were mean heart rate (HR), stress index, low frequency power (LF) representing sympathetic system; mean RR interval, high frequency power representing the parasympathetic system and low frequency power/high frequency power representing global variability (overall well-being).

Interventions

Not applicable.

Main Outcome Measures

HRV indexes of infected unvaccinated and vaccinated subjects.

Results

Statistically significant differences were observed only in mean HR and mean RR interval. UYA (83.5±12.6bpm) had higher mean HR compared with VYA (73.9± 4.91bpm); P=.004; mean difference (MD), −9.58±4.15 bpm; confidence interval, 3.34-15.81. Mean RR was higher in VYA (812.90±52.06ms) than UYA (735.43±123.78ms); P=.02; MD, −77.47±30.6 ms; confidence interval, −139.90 to −15.03. Although the above 2 variables indicate sympathetic and parasympathetic systems, respectively, other indexes were not statistically significant. Most indexes evaluating sympathetic and parasympathetic systems activities were not different between the groups, except for mean HR and RR.

Conclusions

This study suggests that vaccination could help to establish and maintain better autonomic function (lower mean HR and higher mean RR interval) after COVID-19, further experimental research is needed to establish a causal relationship.

Disclosures

none.