We know that Moderna, Pfizer, and now Johnson & Johnson’s Covid-19 vaccines are highly effective against preventing severe disease and hospitalizations. That’s a major win for public health and our strained health care system. But one of the biggest lingering questions about these vaccines is whether they also prevent people from spreading the virus to others.

You might be surprised to know that vaccines can prevent people from getting sick but may not actually stop them from getting infected. This is because some viral particles may still slip past our immune defenses.

It’s likely that Covid-19 vaccines will reduce the…

Many men today have just half the number of sperm their grandfathers had. The shocking discovery was published in 2017 by Shanna Swan, PhD, an environmental and reproductive epidemiologist at the Icahn School of Medicine at Mount Sinai in New York.

After analyzing 185 studies involving nearly 45,000 healthy men, Swan and her team found that over the past four decades, sperm counts among men in Western countries had dropped by more than 50%.

Why the huge decline? Swan says many factors are at play — alcohol use, smoking, body weight, and a lack of exercise are a few. But…

We may soon have a third Covid-19 vaccine. On Wednesday, the Food and Drug Administration (FDA) released a new analysis showing that Johnson & Johnson’s vaccine is both safe and effective at preventing severe symptoms of coronavirus infection.

The vaccine’s efficacy was 72% in the United States and 64% in South Africa, where a more contagious variant has taken hold. This Friday, an FDA advisory committee made up of outside experts will vote on whether the agency should authorize the shot for emergency use. Its approval is highly anticipated because it only requires one dose.

So how does Johnson &…

Reengineering Life

Reengineering Life is a column from Future Human about the ways humans are using biology to reprogram our bodies and the world around us.

A black-footed ferret named Willa died more than 30 years ago, but now her DNA lives on through her clone, Elizabeth Ann. Black-footed ferrets are one of the most endangered species in the United States, and Elizabeth Ann may be key to saving her species from extinction.

Created from a few of Willa’s frozen cells, Elizabeth Ann was born on December 10, 2020. She represents the first successful attempt by scientists to clone an endangered North…

Covid-19 isn’t the first coronavirus outbreak. Before SARS-CoV-2, there was SARS and then MERS. All three viruses likely spilled over from bats. Hundreds more coronaviruses are out there lurking in nature, waiting for the opportunity to infect humans. And next time, it could be far worse than the current pandemic.

While Moderna and Pfizer’s vaccines appear to be highly effective against Covid-19 symptoms, they could be rendered useless if SARS-CoV-2 mutates too much or a completely new coronavirus emerges in the future. …

The next pandemic was supposed to be influenza. After all, three flu pandemics occurred in the last century alone — the Spanish flu of 1918, Asian influenza in 1957, and the Hong Kong flu of 1968.

With the 21st century came the H5N1 avian flu. First, poultry and wild birds succumbed to it. By the mid-2000s, dozens of people in Southeast Asia fell ill, and around 60% of those who contracted it died. Governments predicted a pandemic and drew up preparedness plans, but it never arrived. Meanwhile, a different strain of flu was bubbling up halfway around the world.

In…

Reengineering Life

Reengineering Life is a column from Future Human about the ways humans are using biology to reprogram our bodies and the world around us.

To study how the human brain evolved, scientists have relied on fossilized skulls from our ancient ancestors. These have given us clues about how we differ from our predecessors — that Neanderthal brains were more elongated than our modern ones, for instance — but they can tell only so much. Now, tiny blobs of lab-grown tissue that resemble Neanderthal brains may be able to help fill in some of the gaps.

Researchers at the University of…

Reengineering Life

Reengineering Life is a column from Future Human about the ways humans are using biology to reprogram our bodies and the world around us.

In 2015, a report by a group called the Bipartisan Commission on Biodefense, made up of former members of Congress and past government appointees, warned that the United States was not prepared for a biological threat. The Covid-19 pandemic has confirmed that grim prediction. Already, more than 400,000 Americans have died, and one model predicts that deaths could surge to 630,000 or more by June. …