How immunity from and interaction with seasonal coronaviruses can shape SARS-CoV-2 epidemiology

Abstract

We hypothesized that cross-protection from seasonal epidemics of human coronaviruses (HCoVs) could have affected severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, including generating reduced susceptibility in children. To determine what the prepandemic distribution of immunity to HCoVs was, we fitted a mathematical model to 6 y of seasonal coronavirus surveillance data from England and Wales. We estimated a duration of immunity to seasonal HCoVs of 7.8 y (95% CI 6.3 to 8.1) and show that, while cross-protection between HCoV and SARS-CoV-2 may contribute to the age distribution, it is insufficient to explain the age pattern of SARS-CoV-2 infections in the first wave of the pandemic in England and Wales. Projections from our model illustrate how different strengths of cross-protection between circulating coronaviruses could determine the frequency and magnitude of SARS-CoV-2 epidemics over the coming decade, as well as the potential impact of cross-protection on future seasonal coronavirus transmission.

Keywords: COVID-19; SARS-CoV-2; coronaviruses; cross-protection; immunity.

Fig. 1.

Seasonal HCoV fit. (A) Model fit for seasonal HCoV by age. Black dots show reported HCoV cases; blue are 100 random samples from the posterior. (B) Posterior distributions for the duration of waning and the R₀ of seasonal HCoV. (C) Mean annual attack rate for each age group from 100 samples of the posterior and the last 5 y of the fit.

Fig. 2.

SARS-CoV-2 simulations. (A) Estimated R₀ values for SARS-CoV-2 with different strengths of cross-protection. Points display the R_0,C19, and lines show the range of R_eff,C19 during the simulation. (B) Simulated age-specific serology rates for SARS-CoV-2 by the end of May 2020. Sources are Blood and Transplant donors (BT) (26) and the “What’s the STORY” study (STORY) (27).

Fig. 3.

The 10-y forward projections of seasonal HCoV and SARS-CoV-2 epidemics. Red indicates SARS-CoV-2; blue indicates seasonal HCoVs. The dash-dotted vertical line indicates a change in axis scale due to the much larger SARS-CoV-2 pandemic wave, with that to the left of the dashed line marked by the left axis and that to the right marked by the right axis. Cross-protection strength and estimated SARS-CoV-2 R₀ for the scenario are shown to the left of the figure. (A) Cross-protection from seasonal HCoV to SARS-CoV-2. (B) Bidirectional cross-protection. No control measures were included. Different line types show different samples from the posterior of the seasonal HCoV fit.