A study available on the medRxiv preprint server has estimated the increases of the SARS-CoV-2 Iota (B.1.526) variant for transmissibility, immune escape ability, and infection fatality rate in New York.
The study findings revealed that the Iota variant has considerably higher transmissibility and immune escape potential than previously circulating variants and that it can increase the infection fatality rate by 62%-82% among older adults.
Iota variant emerges in New York
The lota variant, was first identified in New York City in November 2020 and then spread across the US and to 27 countries.
According to one lab study, the Iota variant modestly resists neutralisation by therapeutic monoclonal antibodies and vaccine/infection-induced antibodies. Fortunately however, evidence indicates that the variant does not increase the risk of breakthrough infections in vaccinated or previously infected individuals.
For the study, the scientists analysed multiple epidemiological and population datasets collected in New York City and, with mathematical modeling, estimated the transmission rate, immune evasion ability, and infection fatality risk of the Iota variant.
The prevalence of SARS-CoV-2 was estimated at 16.6% at the end of the first wave, and 41.7% at the end of the second wave. Infections in all age groups were seen with the second wave, compared to mostly older age groups in the first.
Transmissibility and breakthrough
A rapid increase in Iota-infected cases was observed during the second pandemic wave. Before the variant was first discovered in a neighbourhood in early November 2020, a rise in cases was seen in that same neighborhood, which remained higher than other neighbourhoods until Iota became prevalent and raised the baseline.
The researchers estimated that Iota is 15–25% more transmissible than previously circulating variants, with breakthrough infections in 0–10% of the population. These increases made the Iota variant become dominant in New York City from November 2020 to March 2021. Afterward, with the surge of more infectious variant B.1.1.7 (Alpha), Iota prevalence fell.
Despite a reduction in mortality rate following mass vaccination, infection fatality rate was seen to increase in New York City during the second pandemic wave. The researchers estimated that the Iota variant increases the infection fatality rates by 46% for 45–64 year olds, 82% (65–74), and 62% (75+). Compared to previously circulating variants, the Iota variant, overall, caused a 60% increase in infection fatality rate, comparable to that estimated for the Alpha variant.