SARS-CoV-2 antibody response among COVID-19 patients is not affected by parasite co-infection

Background B-cell hypo-responsiveness has been associated with intestinal parasitic co-infection. The effect of parasite co-infection on antibody response to SARS-CoV-2 is unknown. Here, we aimed to determine antibody response to SARS-CoV-2 among COVID-19 patients co-infected with intestinal parasites and those without parasite co-infection. Methods In this prospective cohort study, a total of 589 samples were serially collected from 72 RT-PCR-confirmed patients. Anti-SARS-CoV-2 nucleocapsid protein (NP) antibody titers were measured longitudinally during hospitalization. SARS-CoV-2 infection was confirmed by RT-PCR on samples obtained from nasopharyngeal swabs, while direct microscopic examination, modified Ritchie concentration, and Kato-Katz methods were used to identify parasites and ova from fresh stool samples. Data were analyzed using STATA version 14. Results Of the 72 COVID-19 patients, 39 (54.2%) were co-infected with intestinal parasites while 33 (45.8%) had no parasitic co-infection. Overall, the median cut-off index (COI) for anti-NP antibody titer among COVID-19 patients co-infected with parasites was 6.91 (IQR: 0.55-40.7) compared to 7.51 (IQR: 0.21-59.21) in those without parasites (p=0.764). In addition, 174/261 [66.7% (95% CI: 60.68-72.16)] and 231/328 [70.4% (95% CI: 65.23-75.14)] specimens from COVID-19 patients with parasite co-infection and without parasites, respectively, had anti-SARS-CoV-2 antibody above the cut-off COI value (p=0.328). The positivity rate for anti-SARS-CoV-2 NP < 14 days after symptom onset was 66.3% (95% CI: 60.21-71.85) and 70.0% (95% CI: 64.72-74.74) for those not infected and co-infected with parasites, respectively (p=0.343). In addition, 31/72 (41.9%) of the patients who were negative at the time of enrollment were seroconverted. The trend in anti-NP antibodies among seroconverted individuals with and without parasites is also similar. Conclusions Co-infection with parasitic infection has very little effect on the anti-SARS-CoV-2 antibody immune response. Further studies on the profile of neutralizing antibodies in parasite-endemic areas are warranted to ascertain vaccine efficacy. Author’s summary Pre-existing co-infection with intestinal parasites has been shown to diminish antibody response to a multitude of heterologous pathogens or vaccines. However, the effect of parasite co-infection on antibody response to SARS-CoV-2 is unknown. We determined the anti-nucleocapsid protein (NP) antibody response to SARS-CoV-2 among COVID-19 patients co-infected with intestinal parasites and compared their response to those without parasites. There was no difference in anti-NP positivity rate, seroconversion, or titer level among COVID-19 patients with or without parasitic co-infection. Further studies on the profile of neutralizing antibodies in parasite-endemic areas are warranted to ascertain vaccine efficacy.