Vaccines work well against COVID-19 Delta variant

June 28, 2021
The Delta variant is causing COVID-19 to spread fast. Vaccines work well to protect you. Be careful in crowds. Photo: Getty Images.
The Delta variant is causing COVID-19 to spread fast. Vaccines work well to protect you. Be careful in crowds. Photo: Getty Images.

Perhaps you’ve had COVID-19 already. Perhaps you’ve had one of the two vaccine doses but heard that you may feel under the weather the day after that second shot and are putting it off. Perhaps you figure you’re young and healthy and aren’t going to get all that sick even if you do catch the coronavirus. Or perhaps something else is keeping you from being vaccinated.

If you’re older than 12 and haven’t been vaccinated, buckle up: The Delta variant is sweeping the planet. It is roughly 50% more contagious than the Alpha variant, which itself was roughly 50% more contagious than the “original” coronavirus strains. Multiply that out and we face a variant that spreads more than twice as easily as the coronavirus that burned around the world a year ago. To extend a baseball analogy, if the original coronavirus threw a 100 mph fastball, Alpha hits 150 mph and Delta 225 mph. That sort of competitive advantage is overwhelming.

“The presence of variants is directly correlated to the prevalence of vaccinated persons in the community,’’ said Dr. Richard Zane, chief innovation officer at UCHealth and professor and chairman of Emergency Medicine at the University of Colorado School of Medicine. “Vaccines are like a wall. They prevent the variants from coming in. If you’re not vaccinated, you’re not protected against anything.’’

Dr. Richard Zane receives his COVID-19 vaccine.
Dr. Richard Zane was thrilled to receive his first dose of a new COVID-19 vaccine. Colorado’s hospitalization rates, while improving, were among the 10 highest in the country as of June 12. Photo by Katie Kerwin McCrimmon.

Zane has seen too many people die or become debilitated from the disease the SARS-CoV-2 virus brings. In the face of yet another still-more-infectious variant – B.1.617.2, first detected in India, now known as the Delta variant – now is a moment for action rather than avoidance and the same old excuses, he says.

Destined for domination

Jonathan Samet
Dr. Jonathan Samet

“We’re dealing with a strain that’s much more transmissible, which means it will spread more quickly and propagate the pandemic in Colorado,” said Dr. Jonathan Samet, dean of the Colorado School of Public Health and leader of the Colorado COVID-19 Modeling Group.

That’s not speculation but rather math. In England, Delta comprised 91% of sequenced cases as of June 18. In Colorado, Delta was first detected in late April in Mesa County, home of Grand Junction on the Western Slope. By May 15, Delta had blown past Alpha as the dominant variant there.

As of June 23, just 40% of Mesa County residents were fully vaccinated. Combine Delta with an under-vaccinated population and you get 96% of your ICU beds occupied and 73% of your ventilators running day and night. (Statewide, the figures are 75% ICU occupancy and 35% of critical-care ventilators in use).

It’s not just Mesa County anymore. The Delta variant comprised 75% of new Colorado coronavirus cases as of the week of June 13. Zane says UCHealth now assumes that every new case is Delta.

“Everybody who has COVID has one of the variants, the Delta variant now being predominant. It is simply inevitable,” Zane said.

Vaccines drop Delta

More bad news from across the pond: British researchers assessing 38,805 sequenced cases found the Delta variant to increase the risk of hospitalization 2.6 times.

Now for some good news. If you’re vaccinated, you’re largely protected. Scientists in the UK studied the relative effectiveness of two-shot vaccines such as those of Pfizer and Moderna (Johnson & Johnson’s one-shot vaccine was first approved in late May in the United Kingdom) versus the Alpha and Delta variants. They found the vaccines to be 80% effective in stopping symptomatic disease from the Delta variant – that’s compared to 88% effectiveness of the vaccines against the Alpha variant. Vaccines stopped hospitalization for both Alpha and Delta variants more than 90% of the time.

But whereas the first vaccine dose was 49% effective against the Alpha variant, one dose only stopped the Delta variant 31% of the time. The second shot was critical, the researchers found.

Dr. Richard Zane is confident that vaccines for COVID-19 are safe. Here he poses in an Emergency Department which he transformed.
Dr. Richard Zane. Photo by Cyrus McCrimmon for UCHealth.

Statewide and across the country, illnesses and deaths from the coronavirus have fallen sharply since the winter peak. The vast majority of the vulnerable over-65 set have been vaccinated. In Colorado, roughly half the population has been fully vaccinated, though younger demographics are lagging. Intensive care units do not generally risk being overwhelmed, and if there are local surges, the capacity exists across the health care system to share the load.

But consider that the roughly 300 daily coronavirus deaths across the United States – a trickle compared to the flood of more than 600,000 U.S. deaths since the start of the pandemic – is about triple the number of those who die in car accidents each day in this country. Consider also the now-expired dilemma of easing social distancing measures for the sake of commerce versus the need to keep the health care system from being overwhelmed. Colorado and most of the rest of the country are pretty much open for business. We don’t need to throttle the economy to ensure the health and safety of our fellow man. We simply must join the hundreds of millions who have already been fully vaccinated.

Worldwide, 2.7 billion vaccine doses had been administered as of June 23, to kids as young as 12. That number would be far higher if vaccine supply met demand. The vaccines many of us in the United States can’t be bothered with would be snapped up in a heartbeat most everywhere else.

Virus mutations

It’s hard to say what the Delta variant will mean for the pandemic. Where there’s less vaccination, there will be more cases. How many will there be? How serious will they be? Will waning vaccine efficacy bring reinfections? How will Delta affect the many with weak immune systems – the elderly foremost?

Samet and his modeling group are wrestling with these and many more unknowns. One certainty is that there will be new variants. As Zane put it, “Either viruses don’t enter a host, or they enter a host and try and mutate. That’s just what they do.”

Added Samet, “The virus mutates. It’s always going to, and the most transmissible is going to win out.”

Zane doesn’t blame the virus.

“Sometimes I think I’m maybe a little bit too blunt, but we’re doing this to ourselves,” he said.

He believes that we’ll look back on this pandemic’s countless tragedies and view one of the greatest as our having allowed more transmissible and virulent variants to spread and kill despite having a bounty of incredibly effective vaccines available to stop them.

About the author

Todd Neff has written hundreds of stories for University of Colorado Hospital and UCHealth. He covered science and the environment for the Daily Camera in Boulder, Colorado, and has taught narrative nonfiction at the University of Colorado, where he was a Ted Scripps Fellowship recipient in Environmental Journalism. He is author of “A Beard Cut Short,” a biography of a remarkable professor; “The Laser That’s Changing the World,” a history of lidar; and “From Jars to the Stars,” a history of Ball Aerospace.

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