June 28, 2021 – The highly transmissible Delta variant continues to wreak havoc across the globe. Yet, most vaccines are proving their mettle in limiting the variant’s spread and minimizing its most severe outcomes.
The Delta variant was first identified in India earlier in the year. New cases there surged 3500% in 90 days through mid-May. Thankfully, new cases have since fallen back to early-surge levels.
Public health officials are raising concern about the variant’s impact in Israel and the United Kingdom. Both countries raced ahead early with vaccination programs, reaching large swaths of the citizenry earlier than most countries. These efforts paid dividends quickly, and infection rates plunged in both countries.
Progress has since stalled. The U.K.’s infection rate bottomed out in mid-May and has jumped tenfold since. Israel’s rate has increased each of the past nine days, spiking 880% in this short time. (Still, the rate remains at a low 3.6 new cases per day per 100,000 people.)
Studies point to the Delta variant as the source of surging infections in Israel and the United Kingdom.
On the surface, instances of breakthrough cases – new infections among vaccinated persons, add to public health concerns about the variant’s potential impact. However, a deeper dive into these new cases provides encouraging news: Studying more than 14,000 cases of people infected with the Delta variant, U.K. researchers found the two-dose Pfizer regimen was 88% effective against the variant and 96% effective in preventing hospitalizations.
A smaller study in Israel provides similar results: two-thirds of people reporting new infections were not fully vaccinated. More significantly, while 60% of those not fully vaccinated experienced symptoms, none of the vaccinated persons suffered any symptoms.
To date, the United States has not felt the full impact of the Delta variant. New cases per capita inched up slightly last week yet, remain below levels detected at any point since March 2020. The current rate is on par with rates reported in Israel.
Still, we are observing some turbulence at the state level. Twelve states reported increasing new infections compared to two weeks ago. In nine of these states, cases increased 18% or more in these two weeks. Conversely, half the states saw case rates plummet by 15% or more during the two weeks.
Five states reported new case rates of 10 per 100,000 or greater.
A clue to diverging results is found in disparate vaccination rates by state. As of June 11, full vaccination rates ranged from a low of 37% in Mississippi to 73% in Vermont. (We selected June 11 to acknowledge the two-week lag from vaccination to full immunity impact.)
A statistical analysis of these infection and vaccination rates found a significant (p<0.0004) inverse relationship between infection rates (dependent variable) and vaccination rates (independent variable). In this analysis, each increase of 1% in persons fully vaccinated lowered infection rates by 1.5 new cases per day per million people.
Still, vaccination rates “explained” only half the differences in infection rates between the states. We enhanced the model’s explanatory power by also considering infection rates from two weeks ago (i.e., a state’s “starting point”). By making this addition, the model explanatory effectiveness jumped to 87%.
Setting aside the technical analysis, the conclusion here – and, supported by studies from Israel and the United Kingdom, the vaccines are proving effective in containing even the Delta variant. From the Israel and U.K. studies, even where breakthrough cases emerge among vaccinated people, symptoms are likely to be mild compared to the experiences of the under or unvaccinated.
Contributing writer:
Mark A. Van Sumeren, strategic advisor, Medical Devices & Integrated Delivery Networks
Health Industry Advisor LLC, provides a regular report on COVID-19 numbers for the health care industry.
For more information, or to sign up for the report, contact Mark at Mark.VanSumeren@HealthIndustryAdvisor.com; or visit www.HealthIndustryAdvisor.com.