Protective Effects of BNT162b2 Vaccination on Aerobic Capacity Following Mild to Moderate SARS-CoV-2 Infection, 2022, Blumberg et al

Abstract

Patients previously infected with acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may experience post-acute adverse health outcomes, known as long COVID. The most reported symptoms are fatigue, headache and attention/concentration issues, dyspnea and myalgia. In addition, reduced aerobic capacity has been demonstrated in both mild and moderate COVID-19 patients. It is unknown whether COVID-19 vaccination mitigates against reduced aerobic capacity. Our aim was to compare the aerobic capacity of vaccinated and unvaccinated individuals previously infected with SARS-CoV-2.

Methods: Individuals aged 18 to 65 years with laboratory-confirmed mild to moderate COVID-19 disease were invited to Ziv Medical Centre, Israel, three months after SARS-CoV-2 infection. We compared individuals unvaccinated at the time of infection to those vaccinated in terms of aerobic capacity, measured using symptom-limited cardiopulmonary exercise test (CPET).

Results: We recruited 28 unvaccinated and 22 vaccinated patients. There were no differences in baseline demographic and pulmonary function testing (PFT) parameters. Compared with unvaccinated individuals, those vaccinated had higher V’O2/kg at peak exercise and at the anaerobic threshold. The V’O2/kg peak in the unvaccinated group was 83% of predicted vs. 100% in the vaccinated (p < 0.002). At the anaerobic threshold (AT), vaccinated individuals had a higher V’O2/kg than those unvaccinated.

Conclusions: Vaccinated individuals had significantly better exercise performance. Compared with vaccinated individuals, a higher proportion of those unvaccinated performed substantially worse than expected on CPET. These results suggest that vaccination at the time of infection is associated with better aerobic capacity following SARS-CoV-2 infection.

Open access, https://www.mdpi.com/2077-0383/11/15/4420/htm

 

Strong results and interesting to see these kinds of findings in post-Covid patients in general, not Long Covid patients in particular.

They saw that people who were unvaccinated reached their aerobic threshold sooner:
"The AT was significantly different between the vaccinated and unvaccinated groups, with the AT appearing later for vaccinated participants. The AT is the point at which there is a switch from aerobic to anaerobic metabolism, which results in differences in the ventilation pattern. This difference was observed in our results. Interestingly, there was also a difference between the groups in terms of their subjective feeling at this point, which warrants further research."

Also:
"In our study, there is a significant difference in VE/VO2 at the peak of exercise. This could explain the inability to reach the expected VE in the unvaccinated group due to insufficient O2 delivery to the working muscle..."

 

Given the lack of difference in pulmonary function testing at baseline, the difference is likely due to a difference in loss of fitness post-COVID. Claiming cause and effect is tricky as the participants were not randomised and choosing not to get vaccinated may also be associated with a lower health-seeking behaviours in general (such as willingness to exercise post-recovery from COVID).

The participants in each group were somewhat different too - the unvaccinated group with a mean age that is ~15% older and ~7% higher BMI.