Heterologous immunization with Covishield and Pfizer vaccines against SARS-CoV-2 elicits a robust humoral immune response

Abstract

Understanding the efficacy and durability of heterologous immunization schedules against SARS-CoV-2 is critical, as supply demands and vaccine choices become significant issues in the global vaccination strategy. Here we characterize the neutralizing antibodies produced in two subjects who received combination immunizations against SARS-CoV-2, first with Covishield (Oxford–AstraZeneca) vaccine, followed 33 days later with a second dose (booster) shot of the Pfizer-BioNTech vaccine. Serum samples were collected 25 days following the primary vaccination and 13 days after the secondary Pfizer vaccination. Both subjects exhibited increased levels of isotype IgG and IgM antibodies directed against the entire spike protein following immunizations. These antibodies also exhibited increased reactivity with the receptor binding domain (RBD) in the spike protein and neutralized the infectivity of replicating vesicular stomatitis virus (VSV) that contains the COVID-19 coronavirus S protein gene in place of its normal G glycoprotein. This VSV pseudovirus also contains the reporter gene for enhanced green fluorescent protein (eGFP). Antibody titers against the spike protein and serum neutralization titers against the reporter virus are reported for the 2 heterologous vaccinated individuals and compared to a positive control derived from a convalescent patient and a negative control from an unexposed individual. The Pfizer-BioNTech vaccine increased antibody binding to the spike protein and RBD, and approached levels found in the convalescent positive control. Neutralizing antibodies against the VSV-S pseudovirus in the 2 subjects also approached levels in the convalescent sera. These results firmly validate the value of the Pfizer-BioNTech vaccine in boosting immunity following initial Covishield inoculation.

Reactogenicity and immunogenicity of heterologous prime-boost immunization with COVID-19 vaccine

“…1 Flowchart of the searching protocol and the final articles for systematic review. There studies were excluded because of third dose study [16] , not suitable outcome [17] , case report [54] , [23] , [55] . These studies did not get the inclusion criteria although the studies conducted in combination of the COVID—19 vaccines.…”

A Systematic Review on COVID-19 Vaccine Strategies, Their Effectiveness, and Issues

“…Heterologous combinations such as recombinant (ChAdOx1 nCoV-19) and mRNA (BNT162b2), inactivated (CoronaVac), and recombinant (ChAdOx1 nCoV-19), as well as inactivated (BBIBP) and mRNA (LPP-spike-mRNA), have been studied. To date, a significant augmentation of anti-spike antibody memory B and T cell responses with a few mild side effects, including headache, chills, and fatigue, have been observed [256][257][258][259][260]. Currently, a thorough evaluation of the homologous and heterologous prime booster of COVID-19 vaccines is underway.…”

A Promising Vaccination Strategy against COVID-19 on the Horizon: Heterologous Immunization

“…[ 68 ] reported a significantly higher frequency of activated CD69 + IFN-γ + CD8 + T cells in HtPBV than HmPBV. A single case report deciphered that ChAdOx1 nCoV-19–BNT162b2 HtPBV elicited a robust humoral immune response [ 69 ], exceeding the levels reported by Mulligan et al . [ 70 ] in BNT162b2–BNT162b2 HmPBV.…”