key: cord-1039572-aicih3zp authors: Naaber, P.; Jurjenson, V.; Adamson, A.; Sepp, E.; Tserel, L.; Kisand, K.; Peterson, P. title: Antibody response after COVID-19 mRNA vaccination in relation to age, sex, and side effects date: 2021-04-27 journal: nan DOI: 10.1101/2021.04.19.21255714 sha: b6763c1deb4d45e16d63cc55ab51ff934c49bd85 doc_id: 1039572 cord_uid: aicih3zp Background. The mRNA vaccines for SARS-CoV2 have proven highly effective and are currently used to vaccinate all age groups against COVID-19. Despite their high efficacy in clinical trials, there is limited data on the impact of age, sex, and side effects on vaccine-induced immune responses. Methods. We here studied the development of SARS-CoV-2 Spike protein RBD domain antibodies after two doses of the Pfizer-BioNTech Comirnaty mRNA vaccine in 118 healthy volunteers and correlated their immune response with age, sex, and side effects reported after the vaccinations. Findings. Our findings show a robust immune response to the Spike proteins RBD region after the first and the second vaccination dose. However, we also saw a decline of antibody levels at 6 weeks versus 1 week after the second dose, suggesting a waning of the immune response over time. Regardless of this, the antibody levels at 6 weeks after the second dose remained significantly higher than before the vaccination, after the first dose, or in COVID-19 convalescent individuals. We found a decreased vaccination efficacy but fewer adverse events in older individuals, and that mRNA vaccination is less efficient in older males whereas the detrimental impact of age on vaccination outcome is abolished in females at 6 weeks after the second dose. Interpretation. The Pfizer-BioNTech Comirnaty mRNA vaccine induces a strong immune response after two doses of vaccination but older individuals develop fewer side effects and decreased antibody levels at 6 weeks. The waning of anti-viral antibodies in particular in older male individuals suggests that both age and male sex act as risk factors in the immune response to the SARS-CoV-2 mRNA vaccine. Funding. The study was supported by the Centre of Excellence in Translational Genomics (EXCEGEN), and the Estonian Research Council grant PRG377 and SYNLAB Estonia. The first studies addressing the immune responses in older individuals after the single-dose administration of the SARS-CoV-2 mRNA vaccines have been published. We searched PubMed and medRxiv for publications on the immune response of SARS-CoV-2-mRNA vaccines, published in English, using the search terms "SARS-CoV-2", "COVID-19", "vaccine response", "mRNA vaccine", up to April 15th, 2021. To date, most mRNA vaccine response studies have not been peerreviewed, and data on the role of age, sex and side effects on SARS-CoV-2-mRNA vaccines in real vaccination situations is limited. Some studies have found a weaker immune response in older individuals after the first dose and these have been measured at a relatively short period (within 1-2 weeks) after the first dose but little longer-term evidence exists on the postvaccination antibody persistence. Even less information is available on sex differences or correlations with mRNA vaccine side effects. In this study, we assessed the antibody response up to 6 weeks after the second dose of Pfizer-BioNTech Comirnaty mRNA vaccine in 118 individuals. Our findings show a strong initial immune response after the first dose and an even higher Spike RBD antibody levels at 1 week after the second dose, but these significantly declined at 6 weeks after the second dose. We also found a weaker immune response and faster waning of antibodies in older vaccinated individuals, which correlated with fewer side effects at the time of vaccinations. Furthermore, although overall female and male vaccinees responded similarly, we found that age-related waning of the vaccine-related antibodies was stronger amongst older males whereas in females the impact of age was lost at 6 weeks after the second dose. New mRNA vaccines are now applied worldwide as they have shown high efficacy in clinical trials. Our results show that two doses of Pfizer-BioNTech Comirnaty mRNA vaccine induce a strong antibody response to Spike RBD region but these high levels decline 1.5 months after the second dose in most of the vaccinated individuals. Nevertheless, even at 6 weeks after the second dose, they stay significantly higher than at prevaccination, after the first dose of vaccine, or in Covid-19 postinfection. These findings also implicate that fewer adverse effects may indicate lower antibody response after the vaccination and point to the need for more individualized vaccination protocols, in particular among older people. . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) Introduction 1 New mRNA vaccines have shown high efficacy in clinical trials and are applied worldwide to millions 2 of people. The first two-dose COVID-19 mRNA vaccine, Pfizer-BioNTech Comirnaty (BNT162b2), 3 accepted for emergency use, was found safe and demonstrated 95% efficacy in phase 3 trials. 4 However, so far exists little data about the extent and duration of the antibody responses after the 5 mRNA vaccination, as well as about the factors influencing the efficacy and side effects in real 6 vaccination situations. 7 Although highly efficient in triggering immune responses in clinical trials and initial real situation 8 vaccinations, the first published studies with Pfizer-BioNTech mRNA vaccines have reported weaker 9 immune responses and a higher number of non-responders among older people after the single 1,2 10 and second dose with BNT162b2 vaccine 3,4 . Nevertheless, one study failed to show a significant 11 correlation between age and antibody response after the second vaccination but found a lower 12 magnitude of memory B cell responses with increased age 5 , highlighting a need for further studies to 13 understand the age-related responses to mRNA vaccination. Also, limited information is available 14 about the side effects and their correlation with vaccination outcomes. For example, Goel et al 5 15 found no significant association between the antibody levels and severity of adverse events among 16 vaccinees. Furthermore, the initial studies have not found sex differences in response to COVID-19 17 vaccination 1,5 which has been widely described with several other vaccines 6 .Here we addressed the 18 dynamics of anti-S-RBD IgG vaccination response after first and second doses of the Pfizer-BioNTech 19 Comirnaty mRNA vaccine in healthy volunteers and assessed its correlation with the age, sex, and 20 severity of vaccine side effects. 21 22 Recruitment, sample, and data collection. SYNLAB Estonia employees volunteering to be vaccinated 24 with COVID-19 mRNA Comirnaty (Pfizer-BioNTech) vaccine were invited to participate in the study. 25 Participants signed an informed consent form agreeing with sampling and usage of their clinical data. 26 The blood samplings were performed by trained medical personnel at SYNLAB Estonia. Samples were 27 taken before the first dose of vaccine (baseline), just before the second dose, and 3 weeks after the 28 first dose (time-point 1), 1 week after second dose (time-point 2), and 6 weeks after the second dose 29 (time-point 3). The study participants filled in a questionnaire about the presence of side-effects after 30 the second dose and rated their side-effect severity with scoring from 0 to 3 (Supplementary Table 31 1). All samples and volunteers' data (age, sex, side effects) were stored in a pseudonymized manner. 32 . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 27, 2021. ; https://doi.org/10.1101/2021.04.19.21255714 doi: medRxiv preprint positive mild COVID-19 (n=97) patients collected and described previously. 7 34 The study has been approved by the Research Ethics Committee of the University of Tartu on 35 February 15, 2021 (nr 335/T-21). Patients signed informed consent before recruitment into the study. 36 Antibody testing. Serum samples were analyzed for the antibodies to SARS-CoV-2 Spike protein 37 receptor-binding domain (S-RBD) IgG using quantitative SARS-CoV-2 IgG QN chemiluminescent micro-38 particle immunoassay (CLIA) on ARCHITECT i2000SR analyzer (Abbott Laboratories). The cut-off and 39 the upper detection limit of the test were 50 and 80,000 AU/mL, respectively. Antibody dynamics. Three weeks after the first vaccine dose, we found elevated S-RBD IgG levels in 52 vaccinated serum samples (Figure 1) , measured by the Abbot Laboratories CLIA method, with mean 53 IgG levels of 2,079 AU/mL (range 117 -9,164). Importantly, these S-RBD IgG levels increased 54 significantly after the second vaccination dose (at 1 and 6 weeks) as compared to the first dose 55 (p<0.0001). One week after the second dose, the serum antibody levels were boosted in participants 56 to a mean level of 26,941 AU/mL (range 3,954 ->80,000). However, we found that the S-RBD IgG 57 levels were significantly decreased to 13,971 AU/mL (2,049 -39,789) (p<0.0001) at 6 weeks after the 58 second dose as compared with 1 week after the second dose (Figure 1) . This trend of declining 59 antibody levels between 1 and 6 weeks after the second dose was present in most of the vaccinees, 60 and on average S-RBD IgG levels decreased 45% between these two time-points. In contrast, we 61 found increased S-RBD IgG levels at 6 weeks after the second dose in only 4% of individuals. One 62 individual had slightly elevated S-RBD IgG before vaccination, but negative anti-Nucleocapsid IgG and 63 anti-Spike IgM, also post-vaccination S-RBD IgG was close to average. Although COVID-19 was never 64 . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) (Supplementary Figure 1) . 67 We also compared the post-vaccination results with S-RBD antibodies in COVID-19 recovered 68 patients (Figure 1) . The post-infection IgG levels (mean 3,932) were somewhat higher than in 69 vaccinated persons who received the first dose (p=0.01) but were significantly lower than in those 70 who received two vaccine doses (p<0.0001). 71 Figures 3 and 4) . 79 In a comparison of sex differences, we found a stronger association between age and immune 80 response among males, where the negative correlations between age and S-RBD antibodies were 81 equally strong at all measured post-vaccination time-points -r=-0.58 (after the first dose; p=0.01), r=-82 0.59 (1 week after the second dose; p=0.01), and r=-0.58 (6 weeks after the second dose; p<0.05). In 83 females, the corresponding correlations were weaker and also declined in time r= -0.35 (p<0.001), r=-84 0.28 (p=0.01), and r=-0.21 (ns), suggesting that age together with sex-specific factors affect the 85 vaccination outcomes of mRNA vaccines. 86 Side effects of mRNA vaccination. Vaccination side-effects merit investigation as they are common 87 reasons for vaccine hesitancy. Altogether 93% of participants reported some type of adverse effects. 88 The most common side effects were reported pain or swelling (in 84%) at the injection site, fatigue 89 (64%), malaise (50%), headache (42%), chills (41%), fever, and myalgia (both 34%). The majority of 90 the side effects were present as mild to moderate. However, 20 (22%) persons reported one or 91 several symptoms to significantly disturb his/her daily living activities, and lasting for several days 92 and/or causing absence from work. The total score of side effects (sum of all self-rated side effect 93 scores per patient) ranged between 0 and 27 (mean 7.76). The detailed data on individuals' side 94 effects are presented in Supplementary Table 1 . 95 Factors influencing the vaccine side effects. We found several side effects to positively correlate 96 with the immune response to S-RBD. This was seen with the total score of adverse effects, which 97 . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 27, 2021. ; https://doi.org/10.1101/2021.04.19.21255714 doi: medRxiv preprint significantly associated with the IgG levels at all time points i.e. after the first dose (r= 0.3, p<0.01), 98 and 1 week (r= 0.47, p<0.0001) and 6 weeks after the second dose (r= 0.46, p<0.0001). An even 99 stronger correlation was present with fever at all time-points: r= 0.36 (p<0.001), r= 0.47 (p<0.0001), 100 r= 0.51(p<0.0001), and also other adverse symptoms such as headache, fatigue, malaise, chills, and 101 nausea were positively correlated with the vaccine response (Supplementary Figure 2) . 102 The age of vaccinated individuals negatively correlated with the total score of side effects (r= -0.35, 103 p<0.001) as well as with several specific side effects (Supplementary Figure 2) . Similar to the overall 104 vaccination response, when comparing the two sexes separately, we again found males to have a 105 stronger correlation of vaccine side effects with S-RBD antibody levels. The associations between the 106 score of all side effects and IgG levels were strikingly higher in males than in females at 1 week after 107 the second dose r= 0.87 (p<0.0005) vs r= 0.44 (p<0.0001) and at 6 weeks after the second dose r= We report S-RBD IgG responses after COVID-19 mRNA vaccination showing a significant increase in 113 antibody levels after the second dose followed by a 45% decrease during the next 5 weeks. We found 114 significantly higher IgG levels in vaccinees after 2 doses compared to patients recovered from COVID-115 We found a negative correlation between antibody responses and the age of vaccinated individuals. 117 Age is an important factor that influences vaccine responses, and elderly people have been reported 118 to be poor responders to influenza, hepatitis A and B, and pneumococcal vaccines by developing 119 lower antibody levels and weaker cell-mediated responses. [8] [9] [10] [11] [12] [13] . In addition to diminished post-vaccine 120 responses, older individuals tend to have a more rapid waning of antibodies after the vaccinations. 121 The adverse effect of age on COVID-19 mRNA vaccination has been found after the first dose in some 122 studies. [1] [2] [3] [4] We here show weaker mRNA vaccine response after the first dose and also 1 and 6 weeks 123 after the second dose, confirming the previous results but also show that this difference equalizes 124 and is less significant at 6 weeks after the second dose. Thus, our results indicate the benefit of the 125 second dose for older individuals and its effect to level up the short-term vaccination response in 126 younger and older persons, although the long-term persistence of post-vaccination antibody levels in 127 older populations remains to be studied. 128 . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) Common systemic side effects reported for COVID-19 mRNA vaccines are fatigue, headache, muscle 141 pain, chills, and fever. 14 In our study, 93% of vaccinated individuals reported some type of side-142 effects, which is higher than previously reported 66% of vaccinated seronegative persons. 14 In 143 agreement with our results, the side effects among some groups were seen in 100% of participants of 144 the mRNA vaccine phase 1/2 study. 15 An expected, older participants reported fewer or even no side 145 effects as also seen earlier 4 , and the presence and score of side effects correlated with S-RBD IgG 146 responses. 147 Taken together we report a robust vaccine response after two doses of Pfizer-BioNTech Comirnaty 148 (BNT162b2) vaccine with lower responses and fewer side effects in older individuals. We also found 149 that age-related decreased vaccine response persisted in older males even 6 weeks after the second 150 dose whereas this was no longer present in older female vaccines at this time point. 151 152 Acknowledgments 153 We thank David James (SYNLAB UK) for language corrections. 154 155 . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 27, 2021. ; https://doi.org/10.1101/2021.04.19.21255714 doi: medRxiv preprint . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 27, 2021. ; https://doi.org/10.1101/2021.04.19.21255714 doi: medRxiv preprint Impact of age, ethnicity, sex and prior infection 157 status on immunogenicity following a single dose of the BNT162b2 mRNA COVID-19 vaccine: 158 real-world evidence from healthcare workers A cautionary note on recall vaccination in ex-COVID-19 161 subjects Antibodies Persist Through 6-Months Following 164 2 doses of Moderna COVID-19 Vaccine Age-dependent immune response to the 167 Biontech/Pfizer BNT162b2 COVID-19 vaccination Longitudinal Analysis Reveals Distinct Antibody 170 and Memory B Cell Responses in SARS-CoV2 Naïve and Recovered Individuals Following 171 mRNA Vaccination Factors That Influence the Immune Response to Vaccination Evaluation of SARS-CoV-2 IgG antibody response in PCR 176 positive patients: Comparison of nine tests in relation to clinical data Cytokine production after 179 influenza vaccination in a healthy elderly population Immune response of single dose vaccination against 2009 181 pandemic influenza A (H1N1) in the Taiwanese elderly Hepatitis A/B 183 vaccination of adults over 40 years old: comparison of three vaccine regimens and effect of 184 influencing factors Intradermal hepatitis B vaccination 186 in a large hospital employee population Recombinant Hepatitis B Vaccine in Adults Pneumococcal Vaccine Responses in Elderly Adults Robust spike antibody responses and 192 increased reactogenicity in seropositive individuals after a single dose of SARS-CoV-2 mRNA 193 vaccine Phase I/II study of COVID-19 RNA vaccine 196 BNT162b1 in adults . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. respectively. 205 . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 27, 2021. ; https://doi.org/10.1101/2021.04.19.21255714 doi: medRxiv preprint