Is there a link between pre-existing antibodies acquired due to childhood vaccinations or past infections and COVID-19? A case control study

Abstract

Background There is growing evidence indicating that children are less affected from COVID-19. Some authors speculate that childhood vaccinations may provide some cross-protection against COVID-19. In this study, our aim was to compare the circulating antibody titers for multiple childhood vaccine antigens, as an indicator of the state of immune memory between patients with COVID-19 and healthy controls, with a specific aim to identify the association between disease severity and antibody titrations which may indicate a protective function related to vaccine or disease induced memory. Methods This study is a case-control study including 53 patients with COVID-19 and 40 healthy volunteers. COVID-19 severity was divided into three groups: asymptomatic, mild and severe. We measured the same set of antibody titers for vaccine antigens, and a set of biochemical and infection markers, in both the case and control groups. Results Rubella (p = 0.003), pneumococcus (p = 0.002), and Bordetella pertussis (p < 0.0001) titers were found to be significantly lower in the case group than the control group. There was a significant decline in pneumococcus titers with severity of disease (p = 0.021) and a significant association with disease severity for Bordetella pertussis titers (p = 0.014) among COVID patients. Levels of AST, procalcitonin, ferritin and D-dimer significantly increased with the disease severity. Discussion Our study supports the hypothesis that pre-existing immune memory, as monitored using circulating antibodies, acquired from childhood vaccinations, or past infections confer some protection against COVID-19. Randomized controlled studies are needed to support a definitive conclusion.

Pneumococcal and Influenza Vaccination Rates and Pneumococcal Invasive Disease Rates Set Geographical and Ethnic Population Susceptibility to Serious COVID-19 Cases and Deaths

“…Additionally, rates of pneumococcal vaccinations correlate inversely with the risk of COVID-19 in four separate cohort or case-controlled studies involving tens to hundreds of thousands of patients each [44][45][46][47]. More specifically, Sambul et al [48] found that antibody titers to pneumococcal vaccine antigens were correlated inversely with the risk of COVID-19: non-infected individuals averaged titers that were four times higher than those of COVID-19-infected individuals and (p = 0.002) and people with asymptomatic infections had significantly higher titers than people with severe cases (p = 0.01) [48]. Notably, this study also demonstrated that the risk of COVID-19 and its severity were not associated with immunodepression since titers of measles, tetanus, and Haemophilus influenzae type B (Hib) antibodies were higher among COVID-19 patients than among healthy controls, and the two groups displayed equal antibodies titers against mumps, diphtheria, and varicella-zoster virus [48].…”

“…Nonetheless, other population-level studies have also identified COVID-19 protective effects of influenza vaccination [ 49 , 50 , 51 , 52 , 53 , 54 , 55 ] and MMR vaccination [ 56 , 57 , 58 ], or more specifically, rubella vaccination [ 48 ]. Again, except for the Sambul et al [ 48 ] study, data were not controlled for possible confounding effects of receiving multiple vaccines within a similar timeframe, but in several controlled studies, neither MMR (or measles-containing and rubella-containing vaccines) nor influenza vaccine was associated with protection against COVID-19 case or death rates in population-wide studies [ 5 , 59 , 60 ]. Moreover, even in Sambul et al’s [ 48 ] study, in which they found a significant correlation between higher rubella titers and lower risk of COVID-19, further analysis revealed no relationship ( p = 0.89) between rubella antibody titers and disease severity.…”

“…Again, except for the Sambul et al [ 48 ] study, data were not controlled for possible confounding effects of receiving multiple vaccines within a similar timeframe, but in several controlled studies, neither MMR (or measles-containing and rubella-containing vaccines) nor influenza vaccine was associated with protection against COVID-19 case or death rates in population-wide studies [ 5 , 59 , 60 ]. Moreover, even in Sambul et al’s [ 48 ] study, in which they found a significant correlation between higher rubella titers and lower risk of COVID-19, further analysis revealed no relationship ( p = 0.89) between rubella antibody titers and disease severity. Case-controlled studies of influenza vaccination have reached contradictory conclusions about its effectiveness as a COVID-19 prophylactic: Martínez-Baz et al [ 61 ] and Belingheri et al [ 62 ] found no benefit; Ragni et al [ 63 ] found a benefit only for patients over the age of 65 but not among younger vaccine recipients; Noale et al [ 46 ] found exactly the reverse, with the only benefit among younger recipients; while Massoudi et al [ 64 ] reported significant protection in all age groups.…”

“…Finally, diphtheria-tetanus-pertussis vaccination [ 74 , 75 , 76 , 77 ] and polio vaccination [ 78 ] have also been suggested as possible prophylactics against COVID-19, but at present, no ecological study exists to support these possibilities. Published studies have found no protective benefit [ 5 , 44 , 45 ], and antibody titers against tetanus do not correlate with COVID-19 protection [ 48 ]. However, Sambul et al [ 48 ] reported a very significant inverse correlation between pertussis antibody titers and risk of COVID-19 ( p = 0.0001) in a case-controlled study, but these titers did not distinguish between asymptomatic and severe cases ( p = 0.49) or mild and severe cases ( p = 0.11) of COVID-19 so that while pertussis vaccination may protect against SARS-CoV-2 infection, it does not seem to moderate disease severity.…”

Innate Receptor Activation Patterns Involving TLR and NLR Synergisms in COVID-19, ALI/ARDS and Sepsis Cytokine Storms: A Review and Model Making Novel Predictions and Therapeutic Suggestions

“…In murine models of fatal coronavirus (MERS and SARS) and influenza pneumonias, TLR3-TLR4 synergism is universal, such that antagonizing or deleting TLR4, which is specifically activated by bacterial lipopolysaccharides, prevents death [231][232][233][234]. Indeed, there are multiple reports that vaccinations against S. pneumonia [235][236][237][238][239][240][241][242] and, possibly, Haemophilus influenzae as well [239][240][241] significantly decreases the probability of contracting and dying from COVID-19. In this context, it is too bad that there are not vaccines against Klebsiella pneumoniae, Mycoplasma pneumoniae and Aspergillus fungal infections, as well.…”