Public health leaders urge caution in areas of high Covid-19 variant prevalence
The latest weekly variant cases data shows that cases of VOC-21APR-02 have risen by 3,535 to 6,959 since last week. In some affected areas, hospitalisations are rising; hospital attendances and admissions are predominantly in unvaccinated individuals.
Source:
Public Health England
SPS commentary:
The accompanying risk assessment for the VOC-21APR-02 (B.1.617.2) variant discusses the available evidence in terms of transmissibility between humans, infection severity, immunity after natural infection, and vaccines. This notes that national vaccine effectiveness monitoring shows a reduction in vaccine effectiveness against symptomatic infection after 1 dose of vaccine for B.1.617.2 compared to B.1.1.7 (moderate confidence). Current data suggest this is an absolute reduction of approximately 20% after 1 dose. Iterated analysis continues to show vaccine effectiveness is higher after 2 doses with a small reduction for B.1.617.2 (moderate confidence). There are no data on whether prevention of transmission is affected and insufficient data to assess vaccine effectiveness against severe disease.
The latest vaccine surveillance report (week 21) notes that analysis of vaccine effectiveness against symptomatic disease with VOC-21APR-02 (B.1.617.2) suggest that while there is a reduction in vaccine effectiveness after one dose, any reduction in vaccine effectiveness after 2 doses of vaccine is likely to be small.