Color-enhanced scanning electron microscope image of a human cell infected with SARS-CoV-2 particles, isolated from a patient sample. Virus particles are the small, spherical structures found on the surface of the cell.

Post-Vaccine Covid Infections Are Real. But How Serious Are They?

On Monday, Israel’s Ministry of Health reported a “marked decline in the effectiveness” of the Pfizer-BioNTech Covid-19 vaccine, seemingly due to the prevalence of the new, more transmissible Delta variant of the coronavirus. The vaccine, the Ministry said, was now 64 percent effective at preventing infection and symptomatic illness — down from 94 percent earlier in the year.

As one of the first countries to vaccinate a large portion of its population, Israel has been a closely watched laboratory for Covid-19 vaccine research. And the announcement comes amid rising reports of so-called breakthrough cases of Covid-19, in which fully vaccinated people test positive for the virus.

Researchers have long expected that new variants of the coronavirus would gradually get better at evading vaccines. And while the Israeli data provoked some alarm, many experts questioned the methods used to arrive at the result. Some noted that several other studies have produced more optimistic estimates of the vaccines’ performance against the Delta variant.

The bigger question, perhaps, is what risk, exactly, breakthrough infections actually pose. Researchers are still uncertain how often fully vaccinated people who test positive for Covid-19 actually spread the virus to others. It’s also unclear whether breakthrough infections can trigger long-term effects from Covid-19, sometimes called long Covid. Breakthrough cases are usually asymptomatic or mild: While vaccinated people occasionally develop severe cases of Covid-19, experts say such outcomes are extremely rare. Indeed, even the new Israeli data estimates that the Pfizer vaccine is 93 percent effective at preventing severe cases.

Breakthrough infections, Brown University public health expert Ashish Jha wrote on Twitter this week, “can be miserable.” But, he continued, some vaccinated people may choose to “not care about breakthrough” for one big reason: “You are VERY unlikely to get particularly sick and that’s what matters most.”

Still, reports of breakthrough Covid-19 cases have already led some public health agencies to offer conflicting advice about whether vaccinated people should wear masks. And there’s some evidence that such cases can contribute to widespread misunderstandings about the protective power of vaccines. “Concerns about the efficacy of the Covid-19 vaccines against new coronavirus variants could also deter some from getting vaccinated,” a team of researchers at the Kaiser Family Foundation wrote in late June in an analysis of new survey results. “Nearly half of unvaccinated adults, including six in ten of those in the ‘wait and see’ group say they are worried that the currently available Covid-19 vaccines might not be effective against new strains of coronavirus.”

Also in the News:

• The recent suspension of American sprinter Sha’Carri Richardson from the U.S. Olympic team has raised questions about whether the use of marijuana enhances athletic performance. Richardson, who won the 100-meter race at the U.S. Olympic trials in June, was subsequently suspended for one month after testing positive for marijuana use. Marijuana is now legal in 18 U.S. states — including Oregon, where Richardson said she used the drug — but the World Anti-Doping Agency (WADA) still imposes a ban on its use during periods of competition. The agency has claimed that the drug may enhance performance. The 2011 study that WADA cites as evidence for its ban says that marijuana creates a health risk — but notes that additional research is required to understand if it enhances the performance of athletes. More recent research suggests that there’s little evidence marijuana boosts athletic performance: One recent literature review concluded that cannabis consumption before a sports activity should actually be “avoided in order to maximize performance in sports.” Recently, some major sports leagues, including Major League Baseball, have removed or reduced their restrictions on use of the substance. There are no indications Richardson intended to use marijuana to boost her running; she has said she was trying to cope with the death of her biological mother. (Popular Science)

• Even as officials in the Pacific Northwest began tallying up the damage from last week’s extreme heat wave — including at least 116 deaths in the state of Oregon, widespread loss of wildlife, and damage to infrastructure — meteorologists warned that another Western heat wave is on its way, with triple-digit temperatures predicted in many areas. Like the Pacific Northwest heat wave last week, the new surge in temperature is the result of a phenomenon known as a heat dome. Temperatures could reach 120 degrees Fahrenheit in some parts of California, bringing new health threats and raising the state’s wildfire risk. “This will be a long duration event, where it is not going to cool down much at night,” warned National Weather Service meteorologist Eric Schoening, adding that “it is a dangerous time for the state.” The high temperatures are predicted to extend into Nevada, Arizona, Utah, and other western states. In an analysis of last week’s soaring temperatures, researchers found an obvious contributor to the unprecedented spike: The heat wave “would have been virtually impossible,” climate researcher Geert Jan van Oldenborgh told The New York Times, “without climate change.” (Multiple Sources)

• According to a study published Monday by researchers at the University of Wisconsin-Madison, the state’s gray wolf population has fallen drastically since the species was removed from federal protection last January. The study, published in the peer-reviewed scientific journal PeerJ, estimates that as many as one-third of the state’s wolves have been killed by hunters since the U.S. Fish and Wildlife Service stripped the wolves’ protections during the final days of the Trump administration. The study’s authors estimate that the state’s wolf population has dropped from 1,034 animals in spring 2020 to between 695 and 751 now. Although Wisconsin’s Department of Natural Resources (DNR) originally planned to delay the wolf season until November 2021, a pro-hunting group’s legal efforts resulted in a court order compelling DNR to schedule a hunt for February. The agency intended to limit the kills to 119 wolves, but ended the season early after hunters quickly killed more than 200 animals. Researchers believe the February hunt, coupled with the activities of poachers, caused the steep decline in gray wolf numbers. (The Guardian)

• And finally: the age of the robot pollinator may well be upon us. The Wall Street Journal reports this week on the rising number of global technology startups deploying a mix of mechanical derring-do and artificial intelligence in a race to develop automated pollination — a strategy that backers hope could one day expand agricultural yields well beyond what’s possible by simply relying on natural insect pollinators like bees, or even human workers. The idea of machine-based pollination is not new, but advances in machine learning are lowering many of the barriers to scaling up such technology. Prototype machines outfitted with cameras can now scan rows of greenhouse flowers, for example, identifying those ready for pollinating and delivering a puff of pollen grains to complete the process — crucial for many plant-based food staples, from apples and alfalfa to tomatoes and tequila. Much of the development work in this area is unfolding in Israel, but universities and startups in the U.S., Australia, and elsewhere are hard at work, too, The Journal reports. “Bees work pretty well,” one American tomato grower who’d tested a robot-based system told the newspaper, “but in agriculture, every boost that you can get your hands on is a big deal.” (The Wall Street Journal)

“Also in the News” items are compiled and written by Undark staff. Deborah Blum, Lucas Haugen, Sudhi Oberoi, and Tom Zeller, Jr. contributed to this roundup.

Michael Schulson is a contributing editor for Undark. His work has also been published by Aeon, NPR, Pacific Standard, Scientific American, Slate, and Wired, among other publications.