Decisive Conditions for Strategic Vaccination against SARS-CoV-2

Abstract

While vaccines that protect against SARS-CoV-2 are being approved, the number of available doses remains limited. As it may take months until the production of vaccines can meet the actual demand, the majority of available SARS-CoV-2 vaccines elicits strong immune responses when administered as prime-boost regimens. Since the immunological response to the first ('prime') injection may provide already a substantial degree of protection against infection, it may be more effective---under certain conditions---to vaccinate as many people as possible with only one shot, instead of administering a person a second ('boost') shot. Such a strategic vaccination campaign may help to more effectively slow down the spread of SARS-CoV-2, reduce hospitalizations, and reduce deaths. Yet, the conditions which make single-dose vaccination favourable over prime-boost administrations are not well understood. Here, we formulate a model that helps explore these decisive conditions as a function of the various time scales and epidemiological mechanisms at work. We study how these conditions arise from disease prevalence, vaccination rates, basic reproduction number, prime and prime-boost efficacies, prime-boost intervals, and waning rates. By combining epidemiological modeling, random sampling techniques, and decision tree learning, we find that prime-first vaccination is robustly favored over prime-boost vaccination campaigns, even for high vaccination rates, high disease prevalence, and a relatively low single-dose efficacy.

Controlling Epidemics Through Optimal Allocation of Test Kits and Vaccine Doses Across Networks

“…Furthermore, we assume that only susceptible persons will be vaccinated. Other mechanisms such as prime-boost protocols and time delays between vaccination and onset of immune response can also be accounted for in similar models as detailed in [45].…”

Controlling epidemics through optimal allocation of test kits and vaccine doses across networks

“…This means that vaccinated individuals will no longer be infectious and can be treated as "recovered" after receiving one vaccination dose. Other mechanisms such as prime-boost protocols and time delays between vaccination and onset of immune response can also be accounted for in similar models as detailed in [40].…”

Evolutionary safety of death by mutagenesis

“…The evolution of resistance of SARS-COV2 against vaccination or existing treatments as well as enhanced transmissibility or lethality is a major concern, which has given rise to an impressive number of studies [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] that have been founded on a long history of modelling the emergence of resistance against treatment in other viruses [28][29][30][31][32][33][34][35][36] and epidemiological models for disease spread 18,19,37,38 .…”