Association of Symptoms After COVID-19 Vaccination With Anti-SARS-CoV-2 Antibody Response in the Framingham Heart Study

COVID-19 Vaccine Side Effects and Long-Term Neutralizing Antibody Response : A Prospective Cohort Study

BACKGROUND

Concern about side effects is a common reason for SARS-CoV-2 vaccine hesitancy.

OBJECTIVE

To determine whether short-term side effects of SARS-CoV-2 messenger RNA (mRNA) vaccination are associated with subsequent neutralizing antibody (nAB) response.

DESIGN

Prospective cohort study.

SETTING

San Francisco Bay Area.

PARTICIPANTS

Adults who had not been vaccinated against or exposed to SARS-CoV-2, who then received 2 doses of either BNT162b2 or mRNA-1273.

MEASUREMENTS

Serum nAB titer at 1 month and 6 months after the second vaccine dose. Daily symptom surveys and objective biometric measurements at each dose.

RESULTS

363 participants were included in symptom-related analyses (65.6% female; mean age, 52.4 years [SD, 11.9]), and 147 were included in biometric-related analyses (66.0% female; mean age, 58.8 years [SD, 5.3]). Chills, tiredness, feeling unwell, and headache after the second dose were each associated with 1.4 to 1.6 fold higher nAB at 1 and 6 months after vaccination. Symptom count and vaccination-induced change in skin temperature and heart rate were all positively associated with nAB across both follow-up time points. Each 1 °C increase in skin temperature after dose 2 was associated with 1.8 fold higher nAB 1 month later and 3.1 fold higher nAB 6 months later.

LIMITATIONS

The study was conducted in 2021 in people receiving the primary vaccine series, making generalizability to people with prior SARS-CoV-2 vaccination or exposure unclear. Whether the observed associations would also apply for neutralizing activity against non-ancestral SARS-CoV-2 strains is also unknown.

CONCLUSION

Convergent self-report and objective biometric findings indicate that short-term systemic side effects of SARS-CoV-2 mRNA vaccination are associated with greater long-lasting nAB responses. This may be relevant in addressing negative attitudes toward vaccine side effects, which are a barrier to vaccine uptake.

PRIMARY FUNDING SOURCE

National Institute on Aging.

Innate Responses to the Former COVID-19 Vaccine Candidate CVnCoV and Their Relation to Reactogenicity and Adaptive Immunogenicity

Vaccines are highly effective at preventing severe coronavirus disease (COVID-19). With mRNA vaccines, further research is needed to understand the association between immunogenicity and reactogenicity, which is defined as the physical manifestation of an inflammatory response to a vaccination. This study analyzed the immune response and reactogenicity in humans, post immunization, to the former SARS-CoV-2 mRNA investigational vaccine CVnCoV (CV-NCOV-001 and CV-NCOV-002 clinical trials). Immunogenicity was investigated using whole-blood RNA sequencing, serum cytokine levels, and SARS-CoV-2-specific antibodies. The T cell responses in peripheral blood were assessed using intracellular cytokine staining (ICS) and high-dimensional profiling in conjunction with SARS-CoV-2 antigen-specificity testing via mass cytometry. Reactogenicity was graded after participants' first and second doses of CVnCoV using vaccine-related solicited adverse events (AEs). Finally, a Spearman correlation was performed between reactogenicity, humoral immunity, and serum cytokine levels to assess the relationship between reactogenicity and immunogenicity post CVnCoV vaccination. Our findings showed that the gene sets related to innate and inflammatory immune responses were upregulated one day post CVnCoV vaccination, while the gene sets related to adaptive immunity were upregulated predominantly one week after the second dose. The serum levels of IFNα, IFNγ, IP-10, CXCL11, IL-10, and MCP-1 increased transiently, peaking one day post vaccination. CD4+ T cells were induced in all vaccinated participants and low frequencies of CD8+ T cells were detected by ex vivo ICS. Using mass cytometry, SARS-CoV-2 spike-specific CD8+ T cells were induced and were characterized as having an activated effector memory phenotype. Overall, the results demonstrated a positive correlation between vaccine-induced systemic cytokines, reactogenicity, and adaptive immunity, highlighting the importance of the balance between the induction of innate immunity to achieve vaccine efficacy and ensuring low reactogenicity.

No Evidence That Analgesic Use after COVID-19 Vaccination Negatively Impacts Antibody Responses

Uptake of mRNA vaccines, especially booster immunizations, against COVID-19 has been lower than hoped, perhaps in part due to their reactogenicity. Analgesics might alleviate symptoms associated with vaccination, but they might also impact immune responses. We semiquantitatively measured Ab responses following COVID-19 vaccination in 2354 human participants surveyed about analgesic use after vaccination. Participants who used nonsteroidal anti-inflammatory drugs or acetaminophen after vaccination showed elevated Ab levels against the receptor-binding domain of Spike protein relative to those who did not use analgesics. This pattern was observed for both mRNA-1273 and BNT162b2 and across age groups. Participants who used analgesics more frequently reported fatigue, muscle aches, and headaches than did those who did not use painkillers. Among participants who reported these symptoms, we observed no statistically significant differences in Ab levels irrespective of analgesic use. These data suggest that elevated Ab levels are associated with symptoms and inflammatory processes rather than painkiller use per se. Taken together, we find no evidence that analgesic use reduces Ab responses after COVID-19 vaccination. Recommendation of their use to alleviate symptoms might improve uptake of booster immunizations.

The association between antipyretic analgesics use and SARS-CoV-2 antibody titers following the second dose of the BNT162b2 mRNA vaccine: An observational study

Antipyretic analgesics are used to manage and control symptoms occurring after vaccination, but may hamper immunogenicity or vaccine efficacy. We examined the association between prophylactic or therapeutic use of antipyretic analgesics and SARS-CoV-2 antibody titers for vaccine recipients. Data were obtained from 1,498 staff members of a medical and research institution in Tokyo, Japan, who had received the second dose of the BNT162b2 vaccine. We quantitatively measured anti-SARS-CoV-2 spike protein IgG titers in the participants three months after vaccination. The prophylactic and therapeutic use of antipyretic analgesics was ascertained via a questionnaire. A linear regression model was used to examine the association between antipyretic analgesic use and log-transformed anti-SARS-CoV-2 spike protein IgG titers. Based on model parameters, we estimated geometric mean titers (GMT) and the corresponding 95 % confidence intervals (CI). The results showed that IgG titers in vaccine recipients who used antipyretic analgesics therapeutically was higher than the titers in those who did not (geometric mean ratio [GMR] = 1.26, 95 % CI = 1.17-1.34) with GMTs being 6,147 (95 % CI = 5,833-6,460) and 4,895 (95 % CI = 4,676-5,115) for those who used antipyretic analgesics therapeutically and those who did not, respectively. The association was attenuated, but remained statistically significant after adjusting for symptoms (GMR = 1.14, 95 % CI = 1.06-1.23). We did not find any evidence of significant association in relation to the prophylactic use of antipyretic analgesics (GMR = 0.96, 95 % CI = 0.84-1.10), with GMTs being 5,245 (95 % CI = 4,577-5,913) and 5,452 (95 % CI = 5,258-5,645) for those who used antipyretic analgesics prophylactically and those who did not, respectively. In conclusion, we did not find any evidence of suppression of the humoral response after the second dose of SARS-CoV-2 vaccination by prophylactic or therapeutic use of antipyretic analgesics.

The more symptoms the better? Covid-19 vaccine side effects and long-term neutralizing antibody response

Protection against SARS-CoV-2 wanes over time, and booster uptake has been low, in part because of concern about side effects. We examined the relationships between local and systemic symptoms, biometric changes, and neutralizing antibodies (nAB) after mRNA vaccination. Data were collected from adults (n = 364) who received two doses of either BNT162b2 or mRNA-1273. Serum nAB concentration was measured at 1 and 6 months post-vaccination. Daily symptom surveys were completed for six days starting on the day of each dose. Concurrently, objective biometric measurements, including skin temperature, heart rate, heart rate variability, and respiratory rate, were collected. We found that certain symptoms (chills, tiredness, feeling unwell, and headache) after the second dose were associated with increases in nAB at 1 and 6 months post-vaccination, to roughly 140-160% the level of individuals without each symptom. Each additional symptom predicted a 1.1-fold nAB increase. Greater increases in skin temperature and heart rate after the second dose predicted higher nAB levels at both time points, but skin temperature change was more predictive of durable (6 month) nAB response than of short-term (1 month) nAB response. In the context of low ongoing vaccine uptake, our convergent symptom and biometric findings suggest that public health messaging could seek to reframe systemic symptoms after vaccination as desirable.

Changing Mindsets About Side Effects of the COVID-19 Vaccination: A Randomized Controlled Trial

BACKGROUND

Side-effect concerns are a major barrier to vaccination against COVID-19 and other diseases. Identifying cost- and time-efficient interventions to improve vaccine experience and reduce vaccine hesitancy-without withholding information about side effects-is critical.

PURPOSE

Determine whether a brief symptom as positive signals mindset intervention can improve vaccine experience and reduce vaccine hesitancy after the COVID-19 vaccination.

METHODS

English-speaking adults (18+) were recruited during the 15-min wait period after receiving their second dose of the Pfizer COVID-19 vaccination and were randomly allocated to the symptom as positive signals mindset condition or the treatment as usual control. Participants in the mindset intervention viewed a 3:43-min video explaining how the body responds to vaccinations and how common side effects such as fatigue, sore arm, and fever are signs that the vaccination is helping the body boost immunity. The control group received standard vaccination center information.

RESULTS

Mindset participants (N = 260) versus controls (N = 268) reported significantly less worry about symptoms at day 3 [t(506)=2.60, p=.01, d=0.23], fewer symptoms immediately following the vaccine [t(484)=2.75, p=.006, d=0.24], and increased intentions to vaccinate against viruses like COVID-19 in the future [t(514)=-2.57, p=.01, d=0.22]. No significant differences for side-effect frequency at day 3, coping, or impact.

CONCLUSIONS

This study supports the use of a brief video aimed at reframing symptoms as positive signals to reduce worry and increase future vaccine intentions.

CLINICAL TRIAL INFORMATION

Australian New Zealand Clinical Trials Registry: ACTRN12621000722897p.

Differences in SARS-CoV-2 specific humoral and cellular immune responses after contralateral and ipsilateral COVID-19 vaccination

BACKGROUND

Individual doses of dual-dose vaccine-regimens are sequentially administered into the deltoid muscle, but little attention has so far been paid to the immunological effects of choosing the ipsilateral or the contralateral side for the second dose.

METHODS

In an observational study, 303 previously naive individuals were recruited, who received the second dose of the COVID-19 vaccine BNT162b2 on either the ipsilateral (n = 147) or the contralateral side (n = 156). Spike-specific IgG, IgG-avidity, and neutralizing antibodies were quantified using ELISA and a surrogate assay 2 weeks after dose 2. A subgroup of 143 individuals (64 ipsilateral, 79 contralateral) was analysed for spike-specific CD4 and CD8 T-cells using flow-cytometry.

FINDINGS

Median spike-specific IgG-levels did not differ after ipsilateral (4590 (IQR 3438) BAU/ml) or contralateral vaccination (4002 (IQR 3524) BAU/ml, p = 0.106). IgG-avidity was also similar (p = 0.056). However, neutralizing activity was significantly lower after contralateral vaccination (p = 0.024). Likewise, median spike-specific CD8 T-cell levels were significantly lower (p = 0.004). Consequently, the percentage of individuals with detectable CD8 T-cells was significantly lower after contralateral than after ipsilateral vaccination (43.0% versus 67.2%, p = 0.004). Spike specific CD4 T-cell levels were similar in both groups, but showed significantly higher CTLA-4 expression after contralateral vaccination (p = 0.011). These effects were vaccine-specific, as polyclonally stimulated T-cell levels did not differ.

INTERPRETATION

Both ipsilateral and contralateral vaccination induce a strong immune response, but secondary boosting is more pronounced when choosing vaccine administration-routes that allows for drainage by the same lymph nodes used for priming. Higher neutralizing antibody activity and higher levels of spike-specific CD8 T-cells may have implications for protection from infection and severe disease and support general preference for ipsilateral vaccination.

FUNDING

Financial support was provided in part by the State chancellery of the Saarland to M.S.

Association between reactogenicity and immunogenicity after BNT162b2 booster vaccination: a secondary analysis of a prospective cohort study

OBJECTIVES

A weak correlation between symptom severity and antibody levels after primary immunization against COVID-19 has already been shown. This study aimed to describe the association between reactogenicity and immunogenicity after booster vaccination.

METHODS

This secondary analysis of a prospective cohort study included 484 healthcare workers who received a booster vaccination with BNT162b2. Anti-receptor binding domain (RBD) antibodies were assessed at baseline and 28 days after booster vaccination. Side effects were graded (none, mild, moderate, or severe) and reported daily for 7 days after booster vaccination. Spearman correlation coefficient (rho) was used to determine the correlations between the severity of each symptom and anti-RBD levels before vaccination and 28 days after. The Bonferroni method was used to adjust p values for multiple comparisons.

RESULTS

Most of the 484 participants reported at least one local (451 [93.2%]) or systemic (437 [90.3%]) post-booster symptom. No correlations between the severity of local symptoms and antibody levels were found. Except for nausea, systemic symptoms showed weak but statistically significant correlations with 28-day anti-RBD levels (fatigue [rho = 0.23, p < 0.01], fever [rho = 22, p < 0.01], headache [rho = 0.15, p 0.03], arthralgia [rho = 0.2, p < 0.01], myalgia [rho = 0.17, p < 0.01]). There was no association between post-booster symptoms and pre-booster antibody levels.

DISCUSSION

This study showed only a weak correlation between the severity of systemic post-booster symptoms and anti-SARS-CoV-2 antibody levels at 28 days. Therefore, self-reported symptom severity cannot be used to predict immunogenicity after booster vaccination.

Susceptibility to COVID-19 and Immunologic Response to Vaccination in Patients With Immune-Mediated Inflammatory Diseases

Immune-mediated inflammatory diseases (IMIDs) are a highly heterogeneous group of diseases that share a common etiology of immune dysregulation, such as rheumatoid arthritis, inflammatory bowel disease, and psoriasis, among others. It is estimated that the prevalence of IMIDs ranges between 5% and 7% in developed countries. As current management of IMIDs includes the use of immunomodulatory medications, the resulting weakened immune response can increase the risk of infection, including with SARS-CoV-2 (the causative agent of COVID-19) and reduce response to vaccination, placing these individuals at continued risk of severe outcomes from COVID-19. In this article, we summarize the current literature related to COVID-19 outcomes and the immunogenicity and reactogenicity of COVID-19 mRNA vaccination among patients with rheumatologically dominated IMIDs, as well as the effect of immunomodulatory therapies on these outcomes. We conclude by providing current COVID-19 vaccination recommendations for individuals with IMID.

Anti-SARS-CoV-2 IgG antibody titer after BNT162b2 mRNA COVID-19 vaccination in Japanese patients who underwent renal replacement therapy, hemodialysis, peritoneal dialysis, and kidney transplantation

BACKGROUND

Coronavirus disease (COVID-19) vaccination is recommended for patients undergoing renal replacement therapy (RRT), including hemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KT). However, the difference in the immune response between RRT patients and healthy individuals after mRNA vaccines remains uncertain.

METHODS

This retrospective observational study evaluated the anti-severe-acute-respiratory-syndrome-coronavirus-2 (anti-SARS-CoV-2) IgG antibody acquisition, titers and their changes, normal response rate (reaching titers of healthy individuals), factors associated with a normal response, and effectiveness of booster vaccination in Japanese RRT patients.

RESULTS

Most HD and PD patients acquired anti-SARS-CoV-2 IgG antibodies after the second vaccination; however, their antibody titers and normal response rates (62-75%) were low compared with those of healthy subjects. Approximately 62% of KT recipients acquired antibodies, but the normal response rate was low (23%). Anti-SARS-CoV-2 IgG antibody waning occurred in the control, HD, and PD groups, while negative or very low titers remained in KT recipients. Third booster vaccination was effective in most HD and PD patients. However, the effect was mild in KT recipients - only 58% reached a normal response level. Multivariate logistic regression analyses demonstrated that younger age, higher serum albumin level, and RRT other than KT were significantly associated with a normal response after the second vaccination.

CONCLUSIONS

RRT patients, particularly KT recipients, exhibited poor vaccine responses. Booster vaccination would be beneficial for HD and PD patients; however, its effect in KT recipients was mild. Further COVID-19 vaccinations using the latest vaccine or alternative procedures should be considered in RRT patients.

From Bench to Bedside: Implications of Lipid Nanoparticle Carrier Reactogenicity for Advancing Nucleic Acid Therapeutics

In biomedical applications, nanomaterial-based delivery vehicles, such as lipid nanoparticles, have emerged as promising instruments for improving the solubility, stability, and encapsulation of various payloads. This article provides a formal review focusing on the reactogenicity of empty lipid nanoparticles used as delivery vehicles, specifically emphasizing their application in mRNA-based therapies. Reactogenicity refers to the adverse immune responses triggered by xenobiotics, including administered lipid nanoparticles, which can lead to undesirable therapeutic outcomes. The key components of lipid nanoparticles, which include ionizable lipids and PEG-lipids, have been identified as significant contributors to their reactogenicity. Therefore, understanding the relationship between lipid nanoparticles, their structural constituents, cytokine production, and resultant reactogenic outcomes is essential to ensure the safe and effective application of lipid nanoparticles in mRNA-based therapies. Although efforts have been made to minimize these adverse reactions, further research and standardization are imperative. By closely monitoring cytokine profiles and assessing reactogenic manifestations through preclinical and clinical studies, researchers can gain valuable insights into the reactogenic effects of lipid nanoparticles and develop strategies to mitigate undesirable reactions. This comprehensive review underscores the importance of investigating lipid nanoparticle reactogenicity and its implications for the development of mRNA-lipid nanoparticle therapeutics in various applications beyond vaccine development.

Side Effects of COVID-19 Vaccines in Pregnant and Lactating Mexican Women and Breastfed Infants: A Survey-Based Study

COVID-19 vaccines' safety has been extensively studied; however, further analysis is required in pregnant women, nursing mothers, and breastfed infants. Our aim was to compare the extension and severity of self-reported COVID-19 vaccine side effects in pregnant and breastfeeding women, and breastfed infants. In this cross-sectional study, COVID-19-vaccinated subjects were enrolled using an online survey in Mexico. Women were classified by pregnancy and breastfeeding status at the time of vaccination (n = 3167). After the first or only dose, there was a trend toward fewer systemic effects in pregnant women (p = 0.06). BNT162b2 (Pfizer-BioNTech) had a higher frequency of local symptoms in pregnancy. Lactating women experienced fewer local symptoms after the first or single dose (p = 0.04) and the opposite occurred after the second dose (p = 0.001). ChAdOx1 (AstraZeneca) increased the chances of developing both local and systemic symptoms after the first dose but decreased them after the second dose. The severity was similar across groups, although the result of lack of association in pregnancy requires studies with a larger sample size. Irritability was the most reported symptom in breastfed infants. This study contributes to the knowledge about the side effects in pregnant and lactating women, and breastfed babies.

Assessment of Adverse Reactions, Antibody Patterns, and 12-month Outcomes in the Mother-Infant Dyad After COVID-19 mRNA Vaccination in Pregnancy

Importance

Longitudinal data on COVID-19 messenger RNA (mRNA) vaccine reactogenicity and immunogenicity in pregnancy and for the mother-infant dyad are needed.

Objective

To examine COVID-19 mRNA vaccine reactogenicity and immunogenicity in pregnancy and observe longitudinal maternal and infant outcomes.

Design, Setting, and Participants

This prospective cohort study of pregnant individuals enrolled in the COVID-19 Vaccination in Pregnancy and Lactation study from December 1, 2020, through December 31, 2021, with follow-up through March 31, 2022, was conducted at a large academic medical center in an urban metropolitan area in California. Pregnant individuals receiving COVID-19 mRNA vaccines (mRNA-1273 [Moderna] and BNT162b2 [Pfizer-BioNTech]) were eligible. Of 81 participants enrolled, 5 were excluded after enrollment: 1 terminated pregnancy, 1 received the third vaccine dose prior to delivery, and 3 delivered prior to completing the initial vaccine series.

Exposure

COVID-19 mRNA vaccination at any time during pregnancy.

Main Outcomes and Measures

The primary outcomes were vaccine response as measured by blood Immunoglobulin G (IgG) titers after each vaccine dose and self-reported postvaccination symptoms. Patients' IgG titers were measured in cord blood and in infant blood at intervals up to 1 year of life; IgG and IgA titers were measured in maternal milk. Clinical outcomes were collected from medical records.

Results

Of 76 pregnant individuals included in final analyses (median [IQR] maternal age, 35 [29-41] years; 51 [67.1%] White; 28 [36.8%] primigravid; 37 [48.7%] nulliparous), 42 (55.3%) received BNT162b2 and 34 (44.7%) received mRNA-1237. There were no significant differences in maternal characteristics between the 2 vaccine groups. Systemic symptoms were more common after receipt of the second vaccine dose than after the first dose (42 of 59 [71.2%] vs 26 of 59 [44.1%]; P = .007) and after mRNA-1237 than after BNT162b2 (25 of 27 [92.6%] vs 17 of 32 53.1%; P = .001). Systemic symptoms were associated with 65.6% higher median IgG titers than no symptoms after the second vaccine dose (median [IQR], 2596 [1840-4455] vs 1568 [1114-4518] RFU; P = .007); mean cord titers in individuals with local or systemic symptoms were 6.3-fold higher than in individuals without symptoms. Vaccination in all trimesters elicited a robust maternal IgG response. The IgG transfer ratio was highest among individuals vaccinated in the second trimester. Anti-SARS-CoV-2 IgG was detectable in cord blood regardless of vaccination trimester. In milk, IgG and IgA titers remained above the positive cutoff for at least 5-6 months after birth, and infants of mothers vaccinated in the second and third trimesters had positive IgG titers for at least 5 to 6 months of life. There were no vaccine-attributable adverse perinatal outcomes.

Conclusions and Relevance

The findings of this cohort study suggest that mRNA COVID-19 vaccination in pregnancy provokes a robust IgG response for the mother-infant dyad for approximately 6 months after birth. Postvaccination symptoms may indicate a more robust immune response, without adverse maternal, fetal, or neonatal outcomes.

Demographic and Lifestyle Factors Associated with Patient-Reported Acute COVID-19 Vaccine Reactivity

Patient-reported vaccine reactivity (PRVR) is a major contributor to COVID-19 vaccine hesitancy. PRVR responses to the COVID-19 vaccine may be affected by several modifiable and non-modifiable factors that influence immune function. Understanding the effects of these factors on PRVR can aid in better educating patients on expectations, as well as formulating public health strategies to increase the levels of community vaccination.

Vaccines for the Prevention of Coronavirus Disease 2019 in Older Adults

Institutionalized and community-dwelling older adults have been greatly impacted by the coronavirus disease 2019 (COVID-19) pandemic with increased morbidity and mortality. The advent of vaccines and their widespread use in this population has brought about a dramatic turnaround in COVID-19 outcomes. The immunogenicity and effectiveness of the various vaccine options worldwide are discussed. Optimization of vaccine usage will still be important to maximize protection due to reduced initial immunity, development of variant strains, and fading of immunity over time. There are also lessons learned specific to older populations for future pandemics of novel pathogens.

Risk of Repeated Adverse Effects following Booster Dose of mRNA COVID-19 Vaccine: Results from the MOSAICO Study

The successful deployment of safe and effective vaccines against coronavirus disease 2019 (COVID-19) has been crucial in reducing the global disease burden. Owing to the need for vaccination series over time, continuous observational studies are needed to estimate the COVID-19 vaccine response in real-world conditions. In particular, the detection, assessment, and understanding of adverse effects following immunization (AEFI) with a COVID-19 vaccine are crucial to better address vaccination strategies. Therefore, this study aimed to investigate the risk of repeated AEFI post-administration of a booster dose of mRNA COVID-19 vaccine in a sample of healthcare workers (HCWs) in an Italian teaching hospital. The data on any local and systemic AEFI were studied in multivariate Poisson regression analyses to model the association between the incidence of each postvaccination symptom and its prior reporting after the administration of the previous doses. Overall, compared with the primary vaccination series, the majority of post-third dose AEFI were less reported. The results from multivariable models showed that the likelihood of reporting an AEFI after the third dose was higher in those who experienced the same postvaccination symptom after the second dose (all AEFI except for itch at injection site) and, although not significant for all AEFI, after the first dose. Any associations with age, gender, smoking habits, previous SARS-CoV-2 infection and other characteristics, as well as the health impact of AEFI were also assessed. Taken together, the results from this research support reframe AEFI symptoms as signals of a robust postvaccination reaction as well as of common vaccine response, and they add important data to inform booster vaccination strategies in HCWs and, extensively, in the adult population.

Multiplex Immunoassay Approaches Using Luminex® xMAP® Technology for the Study of COVID-19 Disease

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has been one of the most severe outbreaks of respiratory illness in history. The clinical symptoms of COVID-19 may be similar to flu, although they can be life-threatening, particularly in the elderly and immunocompromised population. Together with nucleic acid detection, serological testing has been essential for the diagnosis of SARS-CoV-2 infection but has been critically important for studying the epidemiology, serosurveillance, and for vaccine research and development. Multiplexed immunoassay technologies have a particular advantage as they can simultaneously measure multiple analytes from a single sample. xMAP technology is a multiplex analysis platform that can measure up to 500 analytes at the same time from the same sample. It has been shown to be an important tool for studying immune response to the various SARS-CoV-2 antigens, as well as for measuring host protein biomarker levels as prognostic indicators of COVID-19. In this chapter, we describe several key studies where xMAP technology was used for multiplexed analysis of SARS-COV-2 antibody responses and host protein expression in COVID-19 patients.