Salivary immunity of elite collegiate American football players infected with SARS-CoV-2 normalizes following isolation

Abstract

The impact of COVID-19 on systemic immunity in the general population has been well characterized, however the short-term effects of COVID-19 infection on innate salivary immunity in elite-level athletes are unknown. Therefore, this study aimed to determine whether elite college football athletes had altered salivary immunity following the CDC-recommended isolation post-SARS-CoV-2 infection. Salivary samples were obtained from fourteen elite football players who tested positive for SARS-CoV-2 (n = 14), immediately after CDC-recommended isolation (average days = 14 ± 2 days) and fifteen controls who remained uninfected with SARS-CoV-2. Biomarkers of innate salivary immunity (sIgA and alpha-amylase), antimicrobial proteins (AMPs, i.e., HNP1-3, lactoferrin, LL-37) and lung inflammation (SPA, SPLI, and Neutrophil Elastase-alpha-1-antitrypsin complex) were measured. Independent student t-tests were used to determine changes in biomarkers between groups. Although all AMP levels were within normal range, Human Neutrophil Defensin 1-3 concentrations and secretion rates were higher in SARS-CoV-2+ compared to SARS-CoV-2-. This suggests that the CDC-recommended isolation period is sufficient to ensure that athletes' salivary immunity is not compromised upon return to sports, and athletes post-COVID-19 infection do not appear to be at greater risk for secondary infection than those with no history of COVID-19.

Figure 1

Concentrations and secretion rates of biomarkers of salivary immunity in athletes who had been infected with SARS-CoV-2 and those who had remained infection-free. No significant differences were found. Salivary IgA (SIgA), alpha-amylase (AMY), dash line (–) represents normal values reported in elite athletes. Concentrations and secretion rates for sIgA (n SARS-CoV-2 +  = 14; n SARS-CoV-2- = 14) are presented as means ± S.D while alpha-amylase (n SARS-CoV-2 +  = 13; n SARS-CoV-2- = 12) are presented as geometric means ± S.D.

Figure 2

Concentrations and secretion rate of biomarkers of salivary immunity in athletes who had been infected with SARS-CoV-2 and those who had remained infection-free. Human neutrophil defensins (HNP1-3), and dash line (–) represents normal values in elite athletes. *p < 0.005. Concentrations and secretion rates for LL-37 (n SARS-CoV-2 +  = 13 ; n SARS-CoV-2- = 6) are presented as means ± S.D while HNP1-3 (n SARS-CoV-2 +  = 14; n SARS-CoV-2- = 10) and Lactoferrin (n SARS-CoV-2 +  = 9; n SARS-CoV-2- = 9) are presented as geometric means ± S.D.

Figure 3

Concentrations and secretion rates of biomarkers of lung inflammation in athletes who had been infected with SARS-CoV-2 and those who had remained infection-free. No significant differences were found in secretory leucocyte protease inhibitor (SLPI), salivary surfactant protein A (SP-A), salivary neutrophil Elastase-alpha-1-antitrypsin complex (NE-A1-AT). Concentrations and secretion rates for SP-A (n SARS-CoV-2 +  = 13; n SARS-CoV-2- = 15), SLPI (n SARS-CoV-2 +  = 14; n SARS-CoV-2- = 15) and NE-A1-At (n SARS-CoV-2 +  = 11; n SARS-CoV-2- = 6) are presented as geometric means ± S.D.