key: cord-0915464-66x3z58o
authors: Jeewandara, C.; Aberathna, I.; Danasekara, S.; Gomes, L.; Fernando, S.; Guruge, D.; Ranasinghe, T.; Gunasekara, B.; Kamaladasa, A.; Kuruppu, H.; Somathilaka, G.; Jayamali, J.; Jayathilaka, D.; Wijayathilake, H.; Pushpakumara, P.; Harvie, M.; Nimasha, T.; de Silva, S.; Wijayamuni, R.; Schimanski, L.; Rijal, P.; Tan, J.; Townsend, A.; Ogg, G.; Malavige, G. N.
title: Comparison of the Immunogenicity of five COVID-19 vaccines in Sri Lanka
date: 2021-12-15
journal: nan
DOI: 10.1101/2021.12.15.21267834
sha: b7d8192541dbe6de0b14a5b4a4413336d6d2e68b
doc_id: 915464
cord_uid: 66x3z58o

We assessed antibody responses 3 months post-vaccination in those who received mRNA-1273 (n=225), Sputnik V (n=128) or the first dose of Gam-COVID-Vac (n=184) and compared the results with previously reported data of Sinopharm and AZD1222 vaccinees. 99.5% of Moderna >94% of AZD1222 or Sputnik V, 72% to 76% of Gam-COVID-Vac (first dose) and 38.1% to 68.3% of Sinopharm vaccinees had ACE2 blocking antibodies above the positive threshold. The ACE2 blocking antibody levels were highest to lowest was Moderna > Sputnik V/ AZD1222 (had equal levels)> first dose of Gam-COVID-Vac > Sinopharm. All Moderna recipients had antibodies above the positive threshold to the ancestral (WT), B.1.1.7, B.1.351.1 and 80% positivity rate for B.1.617.2. Positivity rates of Sputnik V vaccinees for WT and variants, were higher than AZD1222 vaccinees, while Sinopharm vaccinees had the lowest positivity rates (<16.7%). These findings highlight the need for further studies to understand the effects on clinical outcomes.

With the emergence and rapid spread of the Omicron variant, many high income and upper middle income countries have ramped up their vaccination programs by rolling out booster doses to all individuals over 18 years of age 1 , while many individuals in lower income countries are yet to receive their first dose 2 . There are currently seven COVID-19 vaccines which the WHO has given emergency use authorization 3 The efficacy of the different COVID-19 vaccines varies widely, and the levels of neutralizing antibodies (Nabs) elicited by different vaccines have shown to correlate with efficacy rates 5 . A direct comparison between four different vaccines, between two to three months post immunization showed that the Pfizer-BioNTech (BNT162b2), elicited the highest ACE2 blocking antibodies, followed by AZD1222, Sputnik V and Sinopharm 6 . Furthermore, the waning of Nabs and T cell responses with time has been shown to vary widely for different vaccines 7-9 . These differences in the induction of Nabs and their persistence is likely to have a significant impact of the transmission dynamics of the SARS-CoV-2 variants of concern (VOC), especially with the emergence of Omicron. It was shown that a 41-fold decline in Nabs elicited . CC-BY-NC-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) preprint

The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint by the Pfizer-BioNtech vaccine and 30 to 60 fold reduction of Nabs in convalescent plasma was observed for the Omicron variant 10,11 . This immune escape by Omicron was found to be less in those who were previously infected and vaccinated (ref) . In order to prepare for the rapid spread of Omicron globally, many high-income countries have reduced the gap between the 2 nd dose and the booster to three months and to give a booster dose to all adults over 18 years of age 12, 13 .

Although it appears that the Omicron variant significantly evades immunity, induction of higher Nabs through giving a booster dose, is likely to reduce this immune escape (ref) . However, the Nabs levels following booster doses would depend on the Nabs levels post-second dose.

Furthermore, although high-income countries are rapidly deploying booster doses and therefore could possibly reduce the impact due to the rapid transmission of Omicron, the transmission dynamics and clinical disease severity could be different in many lower middle-income countries with lower infection rates, and lower vaccination rates. Sri Lanka has currently fully vaccinated 64% of its population, while 74% have received at least a single dose of the vaccine 4 . Sinopharm (BBIBP-CorV) was the main vaccine used with 11.9 million individuals 14 , which is 56.9% of the total population being vaccinated with this vaccine. Some individuals were also vaccinated with Sputnik V and due to the late arrival of the second dose of Gam-COVID-Vac, many individuals only received the first dose of the Gam-COVID-Vac (rAd26-S) for 3 months, which is marketed as a single dose vaccine. We had previously published the kinetics of antibody and T cell responses to the AZD1222 and the Sinopharm vaccine in the Sri Lankan population separately, which showed significant differences 8,9 . In order to get a better idea regarding the differences in immunogenicity of different vaccines, we wished to build on that data by carrying out a new analysis by carrying out a direct comparison for the . CC-BY-NC-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) preprint

The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint immunogenicity of different vaccines, at the same time point post-vaccination. Therefore, we sought to compare the antibody levels to the receptor binding domain (RBD) of the SARS-CoV-2 virus, VOCs and ACE2 blocking antibodies, 3 months post vaccination, in Sri Lankan individuals who received two doses of Moderna (mRNA-1273), AZD1222, Sinopharm, Sputnik V or a single dose of Gam-COVID-Vac. We further compared the antibody levels in vaccinees who were uninfected and who were naturally infected to determine the changes in antibody levels with natural infection.

. CC-BY-NC-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) preprint In individuals in the 20 to 39 age group, those who received 2 doses of AZD1222 and two doses of Sputnik V had significantly higher (p<0.0001) total antibody responses to the RBD than those who received two doses of the Sinopharm vaccine ( Figure 1A ). Those who received two doses of AZD1222 and both doses of Sputnik V also had significantly higher total antibody responses to the RBD than those who received only the first dose of Sputnik (p<0.0001) and both doses of Moderna (p<0.0001). Those who received both doses of Moderna and one dose of Sputnik had similar levels of total antibodies to the RBD as those who had both doses of Sinopharm ( Figure   1A ).

. CC-BY-NC-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) preprint In individuals in the 40 to 59 age group, those who received 2 doses of AZD1222 and two doses of Sputnik V had significantly higher (p<0.0001) total antibody responses to the RBD than those who received two doses of the Sinopharm vaccine ( Figure 1B) . Individuals who had both doses of these vaccines also had significantly higher (p<0.0001) total antibody responses to the RBD than those who received one dose of Sputnik and both doses of Moderna. Those who had both doses of Moderna had significantly higher responses (p=0.01) than those who received both doses of Sinopharm ( Figure 1B ).

In those who were >60 years of age, the analysis was only carried out for Sinopharm, AZD1222

and Moderna as we had not recruited individuals >60 years who had received Sputnik vaccines.

Those who had received 2 doses of AZD1222 had significantly higher total antibody responses to the RBD than those who had received both doses of Sinopharm (p=0.0003) and both doses of Moderna (p=0.0005) ( Figure 1C ). There was no significant difference between total antibody levels to the RBD in those who had received Sinopharm compared to Moderna (p=0.09). and for Sinopharm 37.7 (IQR 19.6 to 58.9% of inhibition) as previously reported 8,9 .

In the 40 to 59 age group, as reported before, 66.7% of those who received two doses of Those who received one dose of Gam-COVID-Vac also had significantly higher levels (p=0.04) of antibodies than those who received two doses of Sinopharm. Again, those who received two . CC-BY-NC-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) preprint

The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint doses of Moderna had significantly higher (p<0.0001) ACE2 blocking antibodies than those who had two doses of AZD1222 or Sputnik V ( Figure 2B ). The median ACE2 blocking antibody levels for Moderna was 98.9% of inhibition (IQR 98.9 to 99.3% of inhibition), while levels following two doses of Sputnik V was 88.4 (IQR 72.0 to 98.6 % of inhibition) and one dose of Gam-COVID-Vac was 49.7 (IQR 21.4 to 78.0%). The levels for AZD1222 were 78.5% inhibition (IQR 49.1 to 88.4 % of inhibition) and for Sinopharm 37.0% (IQR 21.2 to 56.5% of inhibition) as previously shown by us 8,9 .

As we could not recruit those >60 years of age to study the immunogenicity of the Sputnik vaccines. The analysis was limited to those who received Sinopharm, AZD1222 and Moderna.

We had reported the results of those who received Sinopharm and AZD1222 in >60 years previously 8,9 , which showed 38.1% of those who received Sinopharm and 94.1% of those who received AZD1222 gave a positive response. All individuals (100%) who were >60 and received Moderna both doses (n=44) gave a positive response for the presence of ACE2 blocking antibodies. The ACE2 blocking antibodies were significantly higher in those who received 2 doses of AZD1222 (p=0.0002) and Moderna (p<0.0001) compared to those who received Sinopharm ( Figure 2C ). The ACE2 blocking antibody levels were also significantly higher (p<0.0001) in those who received Moderna compared to those who received AZD1222 ( Figure   2C ). The median ACE2 blocking antibody levels for Moderna was 99.0% (IQR 98.2 to 99.4% of inhibition), while the levels for AZD1222 were 77.6 (IQR 41.0 to 89.4 % of inhibition) and for Sinopharm 21.1 (IQR 8.4 to 44.5% of inhibition) as previously shown by us 8,9 .

. CC-BY-NC-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) preprint 

Our results showed that those who were given two doses of Moderna had significantly higher ACE2 blocking antibodies than those who received the two adenovirus vector vaccines, AZD1222 and Sputnik V. Therefore, we proceeded to investigate the differences in the antibody responses to RBD of the SARS-CoV-2 and VOCs by using the HAT assay, as this assay too has shown to correlate with neutralizing antibodies 15 . The positivity rates of those who received two doses of Moderna and two doses of Sputnik V in different age groups is shown in table 1.

Similar to the results seen with the sVNT assay, all those who received two doses of Moderna had a positive response to the SARS-CoV-2 ancestral strain (WT), alpha and beta variants, whereas positivity rates were 84% in the 20 to 39 and 40 to 59 age groups for delta. In contrast, the positivity rates for the WT and VOC in those who received two doses of Sputnik V were between 67% and 80%. Although these positivity rates were higher than those seen following two doses of AZD1222 (50 to 65%) in 20 to 39 and 40 to 59 year age groups 8 , the positivity rates were less than those following Moderna.

The HAT titres for the WT were significantly higher following Moderna compared to both doses of Sputnik V in 20 to 39 and 40 to 59 age groups (p<0.0001) ( Figure 3A ). HAT titres were also significantly higher for B.1.1.7 in the 20 to 39 (p=0.03) and the 40 to 59 (p=0.02) age groups for Moderna compared to Sputnik V although the difference was less than for the WT ( Figure 3B ).

For B.1.315, a significant difference between HAT titres was only seen in the 40 to 59 age group, with those who received Moderna having significantly higher (p=0.002) levels ( Figure   . CC-BY-NC-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. individuals who received different vaccines were small, we did not analyses the antibody levels for these different assays age groups.

As shown in table 3, the seropositivity rates for the RBD of the SARS-CoV-2 (total antibody levels) and ACE2 blocking antibodies were significantly higher in infected individuals 3 months post-immunization, in those who received two doses of Sinopharm or one dose of Sputnik. For those who received two doses of Moderna, AZD1222 or Sputnik V, there was no difference in the total antibody levels to the RBD. However, the ACE2 blocking antibodies were significantly higher in infected individuals following two doses of Sputnik V vaccines, compared to . CC-BY-NC-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) preprint

The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint uninfected vaccinees, whereas no difference was seen between uninfected and infected individuals who received AZD1222 or Moderna.

In this study we have compared the total antibody levels to the RBD of the SARS-CoV-2 virus, antibody levels to the RBD of VOCs and ACE2 blocking antibodies in those who received two doses of AZD1222, Moderna (mRNA-1273), Sinopharm or Sputnik V or the first dose of Gam-COVID-Vac (Sputnik light), 3 months post-immunization analysed at a single centre in Sri Lanka based on published and new analyses 8,9 . We found that 99.5% of those, in all age groups who received two doses of Moderna had a positive response for the presence of ACE2 blocking antibodies, which is a surrogate measure for the presence of neutralizing antibodies (Nabs), whereas the positivity rates for those who received two doses of AZD1222 or Spuntik V was over 94%. In contrast, the positivity rates following the first dose of Gam-COVID-Vac was 72% to 76% and as we previously reported for Sinopharm it ranged between 38.1% to 68.3% in different age groups 9 . Those who received Moderna also had significantly higher levels of ACE2 blocking antibodies than those who were given other vaccines. While the ACE2 blocking antibody levels following two doses of AZD1222 or Sputnik V were comparable, they were significantly higher than those who were given only one dose of Gam-COVID-Vac or two doses of Sinopharm. Nab levels have shown to strongly correlate with the level of protection against symptomatic COVID-19 5 but the emergence of variants highlights the relevance of immunity beyond spike.

. CC-BY-NC-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 this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint Nab levels have also shown to be a correlate of vaccine efficacy and booster doses were shown to increase the vaccine efficacy by increasing Nab titres 16 . The surrogate Nab test (sVNT) that measures ACE2 blocking antibodies has been widely used as a surrogate measure for Nabs [17] [18] [19] .

While it has been shown that Nabs for current COVID-19 vaccines vary by as much as 25-fold, our data show that there are significant differences in the persistence of Nabs 3 months postvaccination in different age groups that received different vaccines. It has been shown that waning of immunity following two doses of Moderna and AZD1222 associates with breakthrough infections, including an increase in hospitalization rates, especially after 20 weeks 20 although waning of efficacy was less following Moderna 21 . The reduction in break-through infections and hospitalizations correlated with the increase in Nabs following the booster doses 22, 23 . Although there are no data regarding the effectiveness of Sinopharm, one dose of Gam-COVID-Vac and Spuntik V in preventing breakthrough infections, hospitalizations and severe disease, based on the Nabs derived from the sVNT assay, those who received Sinopharm and one dose of Gam-COVID-Vac had substantially less ACE2 blocking antibodies than those who received Moderna, AZD1222 or two doses of Sputnik V. Sinopharm is an inactivated vaccine and so induces immune responses beyond spike which may be relevant, and were not tested here. We have not analysed T cell responses which may also impact, but overall the differences detected here are likely to be relevant with the emergence of the Omicron variant, which has a potential to further evade immunity 24 .

In this study we found that although the mRNA-1273 induced the highest levels of ACE2 blocking antibodies in all age groups and all vaccinees had levels above the cut-off value, the . CC-BY-NC-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. both doses of Sputnik V were between 67.4% to 80%, with titres significantly lower than those who received Moderna, although the positivity rates were higher than those who received two doses of AZD1222 8 . Since the HAT assay was shown to strongly correlate with Nabs levels 15 , it appears that while those who received Moderna had significantly higher Nabs than those who received other vaccines, those who received the two adenovirus vector vaccines had higher antibody levels to the RBD. While the reasons for these differences are not clear, it could be due to mRNA vaccines having stabilizing substitutions in spike protein to maintain the pre-fusion conformation, whereas AZD1222 and Sputnik may not contain these specific substitutions 26,27 . However, it is possible that these differences are seen due to cross reactive antibody responses to different VOCs elicited by different vaccines. While the sVNT that detects ACE2 blocking antibodies would predominantly detect antibodies to the RBD of the WT, the HAT assay could be picking up antibodies that are cross reactive to other VOCs 28 . Therefore, it would be . CC-BY-NC-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 this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint important to conduct a prospective study to understand if these differences in antibody levels and positivity rates observed with different assays translate to risk of infection or clinical disease severity.

With the emergence of Omicron many high income countries have now focused their vaccination programs in rapidly rolling out booster doses 1 . While some countries only gave one dose of a COVID-19 vaccine to those who had been previously had COVID-19 29 , there has not been guidance by many authorities in the need of booster doses for those who were fully vaccinated and infected. Our data show that in those who were infected and received two doses of either the Moderna or AZD1222, there was no difference in the ACE2 blocking antibodies in infected individuals compared to those who were uninfected, whereas for other vaccines the ACE2 blocking antibodies were significantly higher in those who were infected. The ACE2 blocking antibodies were over 99% in those who received one dose of Gam-COVID-Vac, Spuntik V or Moderna, while the median ACE2 blocking antibody levels were 67% and 75.1% for those who received two doses of Sinopharm or AZD1222 respectively. Therefore, infected individuals who received these vaccines could benefit from receiving a booster dose of the vaccine.

In summary, we have investigated antibody levels to the RBD of the ancestral SARS-CoV-2 virus, VOCs and ACE2 blocking antibodies in those who received five types of vaccines, 3 months post-vaccination in Sri Lanka based on published and new analyses from a single centre.

We found that the seropositivity rates, ACE2 blocking antibody levels and antibodies to the RBD of VOCs showed a huge variation between vaccines. The levels of ACE2 blocking antibodies at . CC-BY-NC-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) preprint

The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint 3 months post vaccination was highest was for Moderna, with Sputnik V and AZD1222 eliciting equal levels, followed by those who received the first dose of Gam-COVID-Vac (Sputnik light) and then Sinopharm. These differences in the persistence of immunity to different vaccines is likely to have significant implications in breakthrough infection rates, hospitalization and severe disease in different vaccine recipients.

We are grateful to the Allergy, Immunology and Cell Biology Unit, University of Sri . CC-BY-NC-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. . CC-BY-NC-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) preprint . CC-BY-NC-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. . CC-BY-NC-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) preprint Table 2 The positivity rates and median antibody titres for the RBD of SARS-CoV-2 (total antibodies) and ACE2 blocking antibodies in uninfected and infected vaccine recipients . CC-BY-NC-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. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) preprint

The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint antibodies were also measured in 40 to 59-year-olds who received two doses of Sinopharm (n=48), AZD1222 (36), Sputnik 1 dose (n=25), Sputnik 2 doses (n=77) and Moderna 2 doses (n=132) (B). In those >60 years of age, the analysis was carried out in those who received 2 doses of Sinopharm (n=21), 2 doses of AZD1222 (n=17) and 2 doses of Moderna (n=44). The differences in ACE2 blocking antibodies (% of inhibition) between different vaccines were analysed using the Mann-Whitney test. All tests were two-tailed. The lines indicate the median and the inter quartile range. The positive cut-off value if shown as a red dotted line. 

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The copyright holder for this this version posted December 15, 2021. ; https://doi.org/10.1101/2021.12.15.21267834 doi: medRxiv preprint