COVID-19 vaccine trials and tribulations

In the 1960s, scientists developed a vaccine to protect against RSV, a virus that causes pneumonia in infants. But it had severe, unintended results: The majority of the vaccinated babies who contracted the respiratory syncytial virus became even sicker, and two toddlers died.

In 2016, doctors vaccinated nearly 1 million children in the Philippines against dengue fever. But studies showed that for more than 100,000 of those children, the vaccine increased their risk of developing a deadly condition called plasma leakage syndrome.

As the number of COVID-19 cases tops 2 million worldwide and shutdowns send the global economy into a tailspin, the hunt for a vaccine grows more urgent. But forging ahead too quickly could compromise safety.

“The scientific method is a very deliberate process that has been honed over time,” said H. Holden Thorp, a chemist and editor in chief of the journal Science. He added that speeding up the process to develop a cure or prevention for a new, poorly understood virus is like fixing a plane in flight before the blueprints are complete.

Of some 70 potential COVID-19 vaccines in development, four are in the first phase of human clinical trials. If one or more of the candidate vaccines sails through testing with no complications and appears safe and effective, researchers could mass produce it within a few months. But few vaccines make it through phase one, and even if they do, the process doesn’t end there. The U.S. Food and Drug Administration requires three phases of human trials, each one testing more subjects than the last. Accounting for the entire process, it likely will take at least 12 to 18 months for a COVID-19 vaccine to be ready for a global campaign, Marian Wentworth, president and CEO of the Massachusetts-based Management Sciences for Health, told The Guardian.

While that may seem like ages for people anxious for life to return to normal, it’s warp speed compared to the normal 10- to 15-year process to launch a vaccine. Experts are trying to balance the safety risks posed by rushing vaccine tests against the consequences of delaying treatment and prevention during the pandemic.

The benefits of thorough testing aren’t hypothetical. Pre-clinical trials of vaccines for SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome)—which are coronaviruses like the one that causes COVID-19—uncovered a problem known as vaccine enhancement. In some cases, coronavirus vaccines make the disease worse for those who contract it instead of protecting them.

Scientists at the Pasteur Institute in Paris are working on a vaccine that piggybacks on a licensed measles vaccine, speeding up the testing, licensing, and production processes. Researchers are also testing hundreds of potential treatments for COVID-19. The investigation of new drugs will require the same testing as that of vaccines, but experiments to repurpose already existing drugs may move more quickly.

Bubonic cats

Cougars living in and around Yellowstone National Park, which is mostly in northwestern Wyoming, carry the deadly Yersinia pestis bacteria, which caused the bubonic plague that killed an estimated 30 to 60 percent of Europe’s population in the Middle Ages.

Scientists found nearly half of the 28 cougars in the study had antibodies for the plague, they reported in the journal Environmental Conservation last month. Cougars generally avoid human contact, but hunters and others who handle mountain lions or touch their blood could catch the illness, lead researcher Mark Elbroch told Live Science. Fleas could also pick up the bacteria from cougars and infect humans.

A Boy Scout contracted the plague in the area in 2008 and recovered, and a researcher in Arizona died in 2007 after performing an autopsy on a cougar. Antibiotics could have cured the scientist if his doctors knew he had the disease, the researchers said in the study. —J.B.

Promising test

Researchers have developed the first blood test that can detect more than 50 types of cancer and identify where they originate, often before any clinical signs or symptoms of the disease appear.

In a study due to be published in the journal Annals of Oncology, the test detected cancer through chemical changes to DNA and produced false positives less than 1 percent of the time. In comparison, national breast cancer screening programs detect false positives on about 10 percent of participants. The test accurately predicted the cancer’s site of origin in 93 percent of the cases.

The study included more than 15,000 participants from 142 clinics in North America. Detection rates were fairly low for stage 1 cancers. But they increased with each progressive stage, reaching 43 percent in stage 2, 81 percent in stage 3, and 93 percent in stage 4.

Detecting even half of stage 1 and 2 cancers could save millions of lives every year worldwide, said Fabrice André, editor in chief of Annals of Oncology. —J.B.

Dangerous blaze

The world’s worst nuclear accident occurred when a safety test at the Chernobyl nuclear power plant in Ukraine exploded on April 26, 1986. Last week, a wildfire broke out in the territory surrounding the abandoned plant.

Plants in the region absorb radioactive particles from the soil, which they release when burned, according to a study published in 1996 in the journal Science of the Total Environment. Firefighters in the region battled the blazes for 10 days as the flames crept closer to the decommissioned plant. By Tuesday, officials said rain had put out all the open flames in the area, and the country’s emergency agency said radiation levels in nearby Kyiv, the country’s capital, did not exceed natural background levels. But some grass was still smoldering in the area.

Police have identified a 27-year-old local suspect they believe deliberately started the fire. —J.B.