A British study suggests that Bangladeshi, Pakistani, Muslim, and Sikh groups tested positive for COVID-19 at higher rates than their White and Christian counterparts during surges driven by the Alpha and Delta variants.

In the observational study, published yesterday in BMJ Medicine, a team led by Office for National Statistics researchers examined COVID-19 rates among more than 39 million people aged 10 years and older in England from September 1, 2020, to May 22, 2021 (Alpha) or May 23 to December 10, 2021 (Delta). Average age was 47 years, and 82% were White.

Changing risk patterns

A total of 14.8% of the study population tested positive for COVID-19 during the study. During the Alpha wave, the fully adjusted relative risks of a positive test were highest among Bangladeshi and Pakistani ethnic groups (rate ratios [RRs] vs the White British group, 1.75 and 1.69, respectively).

Relative to the Christian group, the fully adjusted RRs for COVID-19 among Muslim and Sikh religious groups were 1.51 and 1.64, respectively. Other risk factors for a positive test included social deprivation, disadvantaged socioeconomic status, residence in a nursing home, and low English language proficiency.

The disparities among groups varied over time, with an increased relative risk of positivity among Christian, White British, socioeconomically advantaged, and nondisabled people during the Delta wave.

"Changes in the rate ratios observed in wave three compared with wave two could also be due to changes in testing behaviours in response to rollout of vaccination, changes in the perceived risk of infection or reinfection, and policy changes related to isolation periods and compensation after testing positive for SARS-CoV-2," they wrote.

In a related editorial, Felix Chilunga, PhD, and Charles Agyemang, PhD, both of Amsterdam University Medical Centres, called for identification of the reasons behind the decline in risk among disadvantaged populations during the Delta wave. "Answers to these questions might help policymakers in the United Kingdom with the necessary tools to institute relevant public health interventions," they wrote.

The Food and Drug Administration (FDA) within the next few weeks will authorize second bivalent (two-strain) COVID vaccine boosters for the highest risk groups, officials with knowledge of the plans told the Washington Post.

The boosters will be authorized for people who are at least 65 years old or have weakened immune systems and given at least 4 months after the first bivalent booster. FDA officials told the post that the policy change will be "permissive" rather than a formal recommendation. The Centers for Disease Control and Prevention (CDC) is expected to endorse the FDA's action, but it's not clear if its vaccine advisory group will meet to discuss the issue.

In January, the FDA's vaccine advisory committee proposed a plan for annual COVID boosters in the fall for the majority of people, which would involve an updated version of the vaccine. However, given waning protection from mRNA vaccination, there has been some concern that such a plan could leave vulnerable groups with little protection until then. Some countries, including the United Kingdom, have already rolled out second bivalent booster doses for the highest risk groups.