Covid Delta/Indian Variant Doubles Hospitalization Risk For the Unvaccinated

The good news is that the dominant vaccines appear to work well against the Delta variant, meaning that after two doses, there is over 90% protection against hospitalization. 

But those resisting vaccination, even younger people, are putting themselves at greater risk. JL

Helen Collis reports in Politico:

The Delta coronavirus variant, first identified in India, carries double the risk of hospitalization compared with the Alpha variant, according to research released today. While vaccination is providing 70% protection from hospitalization, it’s vital people receive their second dose, since protection shortly after the first dose is limited, the authors stressed. The BioNTech/Pfizer vaccine is 96% effective at preventing hospitalization after two doses, while the Oxford/AstraZeneca vaccine is 92% effective against hospitalization after two doses.

The Delta coronavirus variant, first identified in India, carries about double the risk of hospitalization compared with the Alpha variant, first identified in the U.K., according to research from Scotland released today.

While vaccination is providing roughly 70 percent protection from hospitalization, it’s vital people receive their second dose, since protection shortly after the first dose is limited, the authors stressed.

The Delta variant has become dominant in Scotland since mid-May, and now accounts for around 75 percent of all positive cases, said Chris Robertson, professor of public health epidemiology at the University of Strathclyde, during a briefing. And more younger people are among those hospitalized.

The latest data came ahead of the U.K. Prime Minister Boris Johnson’s announcement this evening on a delay to the easing of pandemic restrictions.

“The Delta variant does increase the risk of hospitalization,” said Jim McMenamin, COVID-19 National Incident Director for Public Health Scotland. "However, what we are able to see from the information available to us is that our vaccines are still highly effective."

The BioNTech/Pfizer vaccine provided 79 percent protection against infection from the Delta variant, compared with 92 percent against the Alpha variant, at least two weeks after the second dose, the study found.

The Oxford/AstraZeneca vaccine, meanwhile, offered 60 percent protection against the Delta variant compared with 73 percent for the Alpha variant.

The researchers, from Universities of Edinburgh and Strathclyde and Public Health Scotland, said the different efficacy rates may reflect that is takes longer to develop immunity with the Oxford/AstraZeneca jab. But they also cautioned it's not possible to directly compare the vaccines since they've been prioritized for different groups of people.

Across both vaccines, the data also showed a "worrying" slightly higher risk of hospitalization with the Delta variant than Alpha after two vaccine doses, noted Robertson.

The results from this analysis, published today as an externally peer-reviewed research letter in the Lancet, was based on community testing among 5.4 million people in Scotland from April 1 to June 6.  

"There is much work that needs to be done to substantiate the information," cautioned McMenamin. "But a full understanding of what those will mean ... can only follow if we are able to combine the analysis that's been done in other parts of the U.K. or internationally."

England's data

Hours after the Scottish data were released, Public Health England released its first analysis of the efficacy of those two vaccines against the Delta variant, with a rosier outlook. It previously said the Delta variant is more transmissible than Alpha and suggested it could cause more hospitalizations, but this assessment is the first one with fuller evidence.

PHE found that the BioNTech/Pfizer vaccine is 96 percent effective at preventing hospitalization after two doses, while the Oxford/AstraZeneca vaccine is 92 percent effective against hospitalization after two doses.

This was based on analysis of 14,019 cases of the Delta variant between April 12 and June 4, 166 of whom were hospitalized; the Scottish analysis of the Delta variant was drawn from 7,723 cases and 134 hospitalizations.

PHE said vaccine efficacy against hospitalization from the Delta variant was “comparable” to the Alpha variant.

Unlike the Scottish data, the PHE data was focused on preventing serious illness needing hospital admission.  The Scottish analysis of vaccine efficacy was based on preventing all infections in the community, including mild cases. 

PHE has previously published analysis showing that one dose is 17 percent less effective at preventing symptomatic illness from the Delta variant compared to Alpha, but there's only a small difference after two doses, it said.

The findings “confirm that the vaccines offer significant protection against hospitalization from the Delta variant,” said Mary Ramsay, head of immunization at PHE. "It is absolutely vital to get both doses as soon as they are offered to you, to gain maximum protection against all existing and emerging variants."