CoronaVac (Sinovac) COVID-19 vaccine-induced molecular changes in healthy human serum by infrared spectroscopy coupled with chemometrics

Abstract

From the beginning of the COVID-19 coronavirus pandemic in December of 2019, the disease has infected millions of people worldwide and caused hundreds of thousands of deaths. Since then, several vaccines have been developed. One of those vaccines is inactivated CoronaVac-Sinovac COVID-19 vaccine. In this proof of concept study, we first aimed to determine CoronaVac-induced biomolecular changes in healthy human serum using infrared spectroscopy. Our second aim was to see whether the vaccinated group can be separated or not from the non-vaccinated group by applying chemometric techniques to spectral data. The results revealed that the vaccine administration induced significant changes in some functional groups belonging to lipids, proteins and nucleic acids. In addition, the non-vaccinated and vaccinated groups were successfully separated from each other by principal component analysis (PCA) and linear discriminant analysis (LDA). This proof-of-concept study will encourage future studies on CoronaVac as well as other vaccines and will lead to make a comparison between different vaccines to establish a better understanding of the vaccination outcomes on serum biomolecules.

Keywords: Attenuated total reflection-Fourier Transform Infrared (ATR-FTIR); COVID-19; Fourier Transform Infrared (FTIR) spectroscopy; multivariate analysis; vaccine; CoronaVac-Sinovac.

Figure 1

Average baseline-corrected infrared spectra of human serum from non-vaccinated (NV) and vaccinated (V) individuals in (A) the 3000–2800 cm–1 and (B) 1800–650 cm–1 regions. The spectra were normalized with respect to the amide A band at 3283 cm–1.

Figure 2

A. Changes in the band area values of (a) CH3 antisym. stretch. (2958 cm−1), (b) Amide I (1637 cm−1), (c) Amide II (1537 cm−1), (d) CH2 bending (1453 cm−1), (e) Amide III (1307 cm−1) (f) PO2 – antisym. stretch. (1241 cm−1), (g) PO2 – sym. stretch. (1079 cm−1) bands, and band area ratios of B. (a) Acyl chain length A2930 /A2958, (b) Lipid/protein A2958+2930+2853+1738+1453/A1637+1537+1307, (c) Protein concentration A1537/A1637+1537, (d) Protein/ nucleic acids, phospholipid A1637/A1241, (e) Protein/ nucleic acids, phospholipids, A1307/A1079, (f) Protein phosphorylation A1241/A2958 from the serum spectra of the non-vaccinated (NV) and vaccinated (V) individuals. The degree of significance was denoted as *p < 0.05.

Figure 3

The differentiation between the serums obtained from non-vaccinated (NV) and vaccinated (V) individuals by unsupervised PCA. (A) Scores and (B) loadings plot were obtained in 3050–2800 cm−1 spectral region for NV and V groups.

Figure 4

The discrimination of the serums obtained from non-vaccinated (NV) and vaccinated (V) individuals by supervised LDA. (A) The discrimination plot was obtained in 3050–2800 cm−1 spectral region for NV and V groups. (B) Classification and (C) confusion matrices of the model classes.

Figure 5

The discrimination of the serums obtained from non-vaccinated (NV) and vaccinated (V) individuals by supervised LDA. (A) The discrimination plot was obtained in 1300–800 cm−1 spectral region for NV and V groups. (B) Classification and (C) confusion matrices of the model classes.