Enlarge / The plague bacteria, Yersina pestis , is a close relative of the toxin-producing species studied here. (credit: Callista Images )

Life-forms with no brain are capable of some astounding things. It might sound like sci-fi nightmare fuel, but some bacteria can wage kamikaze chemical warfare.

Pathogenic bacteria make us sick by secreting toxins. While the release of smaller toxin molecules is well understood, methods of releasing larger toxin molecules have mostly eluded us until now. Researcher Stefan Raunser, director of the Max Planck Institute of Molecular Physiology, and his team finally found out how the insect pathogen Yersinia entomophaga (which attacks beetles) releases its large-molecule toxin.

They found that designated “soldier cells” sacrifice themselves and explode to deploy the poison inside their victim. “YenTc appears to be the first example of an anti-eukaryotic toxin using this newly established type of secretion system,” the researchers said in a study recently published in Nature.

Enlarge (credit: Getty | Maciej Luczniewski )

An alarming outbreak of extensively drug-resistant bacteria linked to eye drops has now sickened 68 people across 16 states, according to the latest update from the Centers for Disease Control and Prevention . At least 16 people have been hospitalized, eight have lost vision, and four have had their eyeballs surgically removed (enucleation). One person has died, which was reported earlier.

The agency first released a health alert on the outbreak February 1. At that point, the outbreak had sickened 55 people in 12 states, with the one death reported in a Washington patient. In an update emailed to Ars on February 22, the CDC said the case count had reached 58, with five cases of vision loss and one enucleation.

The continued rise in cases and severe outcomes highlights the challenge of fighting the germ behind the outbreak, which is an extensively drug-resistant form of Pseudomonas aeruginosa . It has the unwieldy name of Verona Integron-mediated Metallo-β-lactamase (VIM) and Guiana-Extended Spectrum-β-Lactamase (GES)-producing carbapenem-resistant Pseudomonas aeruginosa—or VIM-GES-CRPA, for short.

Enlarge / An elderly female patient with COVID-19 is treated at No. 2 People's Hospital of Fuyang City in China. (credit: Getty | Sheldon Cooper/SOPA Images/LightRocke )

With China's zero-COVID policy abruptly scrapped last month, the pandemic virus is now ripping through the country's population, and health experts are bracing for a wave of devastation as peak transmission shifts from urban centers to more vulnerable rural communities. The dire situation is expected to be "dramatically enhanced" by mass travel later this month for celebrations of the Lunar New Year on January 22.

Multiple modeling studies have suggested that China could see around 1 million deaths in the coming weeks as the country reopens amid a raging outbreak. Last month, modeling by The Economist estimated that 96 percent of China's 1.4 billion people could catch the virus within the next three months, resulting in 1.5 million deaths . Of those deaths, 90 percent would be among people aged 60 and over.  Another modeling study, partly funded by China's Centers for Disease Control and Prevention, also estimated that 957,600 would die in the coming weeks if the country doesn't swiftly roll out fourth-dose COVID-19 vaccines.

Because China was previously able to keep COVID-19 waves at bay with its zero-tolerance policies, most of the country's immune protection derives from vaccination rather than prior infection or hybrid protection. Around 90 percent of China's population has had two shots of COVID-19 vaccines, but fewer than 60 percent have received a third shot as a booster dose. And even for those who have gotten a third dose, many of those doses were taken months ago, and peak protection has passed. Vaccination coverage among the elderly is particularly worrying. About 30 percent of people aged 60 and over have not gotten a third dose, and for people aged 80 and over, a startling 60 percent have not gotten a third dose.

Enlarge / A woman watches white flags on the National Mall on September 18, 2021, in Washington, DC. Over 660,000 white flags were installed here to honor Americans who have lost their lives to COVID-19. (credit: Getty | Chen Mengtong )

Without COVID-19 vaccines, the US would have seen four times more deaths from the pandemic virus—an additional 3 million lives lost—as well as nearly four times more hospitalizations, 1.5 times more infections, and an additional $1.5 trillion in medical bills since December of 2020.

Those are the top-line results from a new modeling study by the Commonwealth Fund , which simulated the unmitigated effects of COVID-19 in the US from December 2020 to November 2022.

The age-stratified model accounted for US demographics, the prevalence of disease-enhancing comorbidities, social networks, limited social contact during pandemic restrictions, COVID-19 case data, hospitalization rates, vaccination administration eligibility and rates, vaccine efficacy estimates, waning protection from vaccination and infection, and the characteristics of five SARS-CoV-2 variants (Iota, Alpha, Gamma, Delta, Omicron). The model was calibrated to replicate real-world data of cases, hospitalizations, and deaths before the researchers removed vaccines from the scenario.

Enlarge / A COVID-19 testing tent stands in Times Square on April 27, 2022, in New York City. (credit: Getty | Spencer Platt )

Enduring an initial omicron infection may not spare you from omicron's subvariants, according to preliminary data from South Africa.

The country is currently at the start of a new wave of infections, primarily driven by two omicron coronavirus subvariants, BA.4 and BA.5. Despite a towering wave of cases from the initial BA.1 omicron variant in December that infected a large chunk of the country, new omicron cases increased 259 percent in the last two weeks, according to data-tracking by The New York Times. Hospitalizations are also up, and deaths have increased by 18 percent.

Preliminary data posted online last week helps explain why cases are once again surging—the BA.4 and BA.5 omicron subvariants can evade neutralizing antibodies generated by infections from BA.1. For the study, led by virologist Alex Sigal of the Africa Health Research Institute, researchers pitted neutralization antibodies from people infected with BA.1 up against BA.4 and BA.5 in a lab. They had samples from 24 unvaccinated people infected with BA.1 and 15 vaccinated people who had also had a BA.1 infection (eight people were vaccinated with the Pfizer/BioNTech vaccine, and seven had the Johnson & Johnson vaccine).