Waning of specific antibodies against Delta and Omicron variants five months after a third dose of BNT162b2 SARS-CoV-2 vaccine in elderly individuals

Abstract

The emergence of new SARS-CoV-2 variants, such as the more transmissible Delta and Omicron variants, has raised concerns on efficacy of the COVID-19 vaccines. Here, we examined the waning of antibody responses against different variants following primary and booster vaccination. We found that antibody responses against variants were low following primary vaccination. The antibody response against Omicron was almost non-existent. Efficient boosting of antibody response against all variants, including Omicron, was observed following a third dose. The antibody response against the variants tested was significantly higher at one month following booster vaccination, compared with two months following primary vaccination, for all individuals, including the low antibody responders identified at two months following primary vaccination. The antibody response, for all variants tested, was significantly higher at four months post booster than at five months post primary vaccination, and the proportion of low responders remained low (6-11%). However, there was significant waning of antibody response in more than 95% of individuals at four months, compared to one month following booster. We also observed a robust memory B cell response following booster, which remained higher at four months post booster than prior to booster. However, the memory B cell responses were on the decline for 50% of individuals at four months following booster. Similarly, while the T cell response is sustained, at cohort level, at four months post booster, a substantial proportion of individuals (18.8 – 53.8%) exhibited T cell response at four months post booster that has waned to levels below their corresponding levels before booster. The findings show an efficient induction of immune response against SARS-CoV-2 variants following booster vaccination. However, the induced immunity by the third BNT162b2 vaccine dose was transient. The findings suggest that elderly individuals may require a fourth dose to provide protection against SARS-CoV-2.

Pre-existing immunity to SARS-CoV-2 before the COVID-19 pandemic era in Cameroon: A comparative analysis according to HIV-status

“…The later could also be justified by a previous contact with other coronaviruses sharing common antigenic profiles ( 4 , 8 ), which could be either HKU1, NL63, OC43 or 229E. Moreover, the circulation of these specific coronaviruses within Central Africa had never been described before the COVID-19 outbreak ( 22 , 23 ).. Assessing the titer and immunogenicity of these specific pre-pandemic SARS-CoV-2 antibodies through broadly neutralizing assays will help confirm this hypothesis and further characterize this cross-immunity to understand its effect on SARS-CoV-2 variants and sub-lineages circulating nowadays ( 24 ). On one hand, we observed a higher sero-positivity SARS-CoV-2 antibodies among males as compared to females, likely driven by the differential level of ACE-2 receptors among men as compared to women ( 8 , 25 ).…”

mRNA Vaccines against SARS-CoV-2: Advantages and Caveats

“…T478K, Q293K, Q498R and E484A contributed to an elevated transmission rate and evasion from neutralizing antibodies [ 104 ]. Due to this enhanced escaping capacity, the protection achieved with BNT162b2 and mRNA-1273 vaccines decreased to 30% after three doses, and to 47.2% in older adults [ 93 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 ]. This variant is still evolving, leading to Omicron sub-variants such as BQ, XBB and BF.7, with high capacities to avoid neutralizing antibodies elicited by the original vaccines [ 108 , 113 ].…”

Age, comorbidities, c-reactive protein and procalcitonin as predictors of severity in confirmed COVID-19 patients in the Philippines

“…The severity of COVID-19 infection was shown to be reduced in vaccinated elderly individuals [ 69 ], while in this study the older age was a significant factor associated with increased severity. However, the vaccine immunity in this vulnerable group seems to be transient and gradually declines over time [ 70 ]. Besides, no major changes in blood parameters involved in this present study or the risk of hematological abnormalities following COVID-19 vaccination was currently observed [ 71 , 72 ], supporting the possible utility of these factors in vaccinated cases.…”