This is an excerpt from Second Opinion, a weekly roundup of health and medical science news emailed to subscribers every Saturday morning. If you haven’t subscribed yet, you can do that by clicking here.
New Canadian data suggests the bold strategy to delay and mix second doses of COVID-19 vaccines led to strong protection from infection, hospitalization and death — even against the highly contagious delta variant — that could provide lessons for the world.
Preliminary data from researchers at the British Columbia Centre for Disease Control (BCCDC) and the Quebec National Institute of Public Health (INSPQ) shows the decision to vaccinate more Canadians sooner by delaying second shots by up to four months saved lives.
The researchers excluded long-term care residents from the data, who are generally at increased risk of hospitalization and death from COVID-19, in order to get a better sense of vaccine effectiveness in the general population — and the results were exceptional.
The analysis of close to 250,000 people in B.C. from May 30 to Sept. 11 found two doses of any of the three available COVID-19 vaccines in Canada were close to 95 per cent effective against hospitalization — regardless of the approved vaccination combination.
That means for every 100 unvaccinated people severely ill in Canadian hospitals, 95 of them could have been prevented by receiving two doses of either the AstraZeneca-Oxford, Pfizer-BioNTech and Moderna vaccines, or some combination of the three.
Dr. Danuta Skowronski with the B.C. Centre for Disease Control laid the groundwork for the decision to hold back second doses and says the early vaccine effectiveness data is extremely encouraging. (Harman/CBC)
Dr. Danuta Skowronski, a vaccine effectiveness expert and epidemiology lead at the BCCDC whose research laid the groundwork for the decision to hold back second doses based on the “fundamental principles of vaccinology,” says the early data is extremely encouraging.
“We were very pleased to see during the period when the delta variant was not just circulating, but predominating, that we had such high protection nonetheless against both infection and hospitalization,” the lead researcher on the analysis told CBC News.
“Protection was even stronger when the interval between the first and the second doses was more than six weeks apart.”
In fact, the research showed that protection against COVID-19 infection from two doses of the Pfizer vaccine rose dramatically when the first and second shots were spread out — from 82 per cent after three or four weeks, to 93 per cent after four months.
“For those who received the AstraZeneca vaccine as their first dose, their protection against any infection was lower than for mRNA vaccine recipients, but they had comparable protection against hospitalization and that’s the main goal,” she said.
“But for those who received a first dose of AstraZeneca and a second dose as an mRNA vaccine, their protection was as good as those who had received two mRNA vaccines. So that’s also a really important finding from this analysis.”
While the work is still being finalized and has not yet been submitted as a pre-print or undergone peer review, the researchers felt it’s important to get their early data out now to inform the public and policymakers here and abroad about the positive results.
“The mix-and-match schedules are protecting well, and my preference would be that those countries who don’t recognize that get to see our data as soon as possible,” she said, adding that the findings were sent to U.S. officials for review of international travel policies.
“My hope is that when they see the evidence that they will change those policies, which are frankly inconsistent with the science.”
Quebec data backs up findings from B.C.
In Quebec, thousands of kilometres away and with a different population, demographic makeup and early vaccine rollout approach — the results of a twin study that will be published alongside the B.C. data were astonishingly similar.
Of the 181 people who died from COVID-19 from May 30 to Sept. 11 in Quebec, just three were fully vaccinated. Researchers say that corresponds to a vaccine effectiveness against death upwards of 97 per cent based on a population analysis of nearly 1.3 million people.
Similar to the B.C. data, the Quebec research also showed more than 92 per cent protection from hospitalizations — with Pfizer, Moderna or AstraZeneca vaccines — against all circulating coronavirus variants of concern in Canada at that time, including delta.
“The takeaway is whatever vaccine people had, if they got two doses they should consider that they are very well protected against severe COVID-19,” said Dr. Gaston De Serres, an epidemiologist at the INSPQ. “That’s the main message.”
The analysis found Pfizer and Moderna vaccines were 90 per cent effective at preventing COVID-19 infections — either asymptomatic, symptomatic, or those needing hospital care — a protection rate equal to those with an AstraZeneca and mRNA vaccine combination.
For people who received two doses of AstraZeneca, the research suggests a slightly lower level of protection from infection — but one that is still remarkably high at 82 per cent.
The research showed that protection against COVID-19 infection from two doses of the Pfizer vaccine rose dramatically when the first and second shots were spread out. (Darryl Dyck/The Canadian Press)
De Serres says the National Advisory Committee on Immunization (NACI) and the Quebec Immunization Committee (CIQ) are looking at whether additional doses may be needed for that group, but says it’s “not as pressing” given the strong protection from hospitalization.
“For the time being, just stay put. If there is a recommendation for you to get an additional RNA dose you’ll know in time,” De Serres said. “But feel that what you’ve got is still a very good regimen to protect you against what we fear most — which is severe COVID-19.”
The NACI recommendation in March to delay second doses of all three COVID-19 vaccines by up to four months was not without controversy at the time, and no doubt led to confusion among many Canadians about whether they were adequately protected.
Canada’s Chief Science Adviser Mona Nemer said in early March that the strategy amounted to a “population level experiment,” while at the same time health officials tried to reassure the public that the approach was safe and effective.
Deepta Bhattacharya, an immunologist at the University of Arizona who was not involved in the study, says the results are “very encouraging” and provide evidence of “improved real world protection” from delaying second doses.
But he admits even he was initially skeptical.
“I was uneasy about it in large part because I just wasn’t sure how well the protection would hold up in the interim,” he said. “Obviously it turned out well … but it was risky, and that gamble paid off.”
Bhattacharya says the Canadian data now provides real world evidence that vaccinated people produce more antibodies if their second shot is delayed, and the quality of those antibodies may actually improve — which could explain the better protection against delta.
“What I’m really wondering now going forward is whether the recommendations are going to fundamentally change as to when we should get that second shot,” he said, referring to other countries around the world. “I wish I’d gotten mine later now in retrospect.”
Keeping ‘eye on the prize’ means avoiding hospitalization
The data also has implications on whether average Canadians need booster shots, particularly given that emerging real world data in other countries like the U.S., Israel and Qatar show evidence of waning immunity that has prompted the rollout of third doses.
But experts caution that while countries reporting diminished vaccine effectiveness against COVID-19 infection may be making headlines, the more important factor is that the studies largely show the vaccines have prolonged protection against severe COVID-19 — meaning hospitalization and death.
“We really should keep our eyes on the prize, which is preserving healthcare system capacity and preventing unnecessary suffering,” said Skowronski. “We’re not going to prevent every case of COVID-19. Our goal was never to prevent the sniffles. Our goal was to prevent serious outcomes.”
Still, the B.C. and Quebec data showed “no signs” of waning immunity in the general population four months after the second mRNA dose and strong protection against infection of more than 80 to 90 per cent maintained. The analysis doesn’t go beyond five months, but the researchers will continue monitoring vaccine effectiveness.
“We should be reassured that our vaccine effectiveness from this calculation, from what I’ve seen, will be robust with its protection,” said Alyson Kelvin, an assistant professor at Dalhousie University and virologist at the Canadian Center for Vaccinology and the Vaccine and Infectious Disease Organization in Saskatoon who was not involved in the research.
“We must continue to have public health measures in place as well as expect at some point we might need a booster, but data like this will inform when we do and right now it’s suggesting that we don’t need it yet — but we have to keep vigilant.”
WATCH | Canada recommends COVID-19 booster shots for long-term care residents:
NACI recommends COVID-19 booster shots for seniors in long-term care
11 days ago
Amid a global debate over COVID-19 vaccine boosters, the National Advisory Committee on Immunization is recommending third doses for Canada’s most vulnerable, especially seniors in long-term care homes. 1:58
Skowronski says that while she supports giving long-term care residents and immunocompromised people third doses of COVID-19 vaccines to increase their protection based on emerging data, including from Canada, there isn’t enough evidence yet for average Canadians.
Until then, she says Canadians should feel well protected against severe outcomes from COVID-19 in the delta-driven fourth wave if they’re fully vaccinated with any of the approved vaccine combinations in Canada.
“We’re going to have to learn to live with SARS-CoV-2, including in it’s very many future iterations,” she said.
“But so long as we can prevent severe outcomes and maintain healthcare system capacity, we can come to a kind of a mutual understanding with this virus.”
NEW YORK (AP) — The U.S. syphilis epidemic slowed dramatically last year, gonorrhea cases fell and chlamydia cases remained below prepandemic levels, according to federal data released Tuesday.
The numbers represented some good news about sexually transmitted diseases, which experienced some alarming increases in past years due to declining condom use, inadequate sex education, and reduced testing and treatment when the COVID-19 pandemic hit.
Last year, cases of the most infectious stages of syphilis fell 10% from the year before — the first substantial decline in more than two decades. Gonorrhea cases dropped 7%, marking a second straight year of decline and bringing the number below what it was in 2019.
“I’m encouraged, and it’s been a long time since I felt that way” about the nation’s epidemic of sexually transmitted infections, said the CDC’s Dr. Jonathan Mermin. “Something is working.”
More than 2.4 million cases of syphilis, gonorrhea and chlamydia were diagnosed and reported last year — 1.6 million cases of chlamydia, 600,000 of gonorrhea, and more than 209,000 of syphilis.
Syphilis is a particular concern. For centuries, it was a common but feared infection that could deform the body and end in death. New cases plummeted in the U.S. starting in the 1940s when infection-fighting antibiotics became widely available, and they trended down for a half century after that. By 2002, however, cases began rising again, with men who have sex with other men being disproportionately affected.
The new report found cases of syphilis in their early, most infectious stages dropped 13% among gay and bisexual men. It was the first such drop since the agency began reporting data for that group in the mid-2000s.
However, there was a 12% increase in the rate of cases of unknown- or later-stage syphilis — a reflection of people infected years ago.
Cases of syphilis in newborns, passed on from infected mothers, also rose. There were nearly 4,000 cases, including 279 stillbirths and infant deaths.
“This means pregnant women are not being tested often enough,” said Dr. Jeffrey Klausner, a professor of medicine at the University of Southern California.
What caused some of the STD trends to improve? Several experts say one contributor is the growing use of an antibiotic as a “morning-after pill.” Studies have shown that taking doxycycline within 72 hours of unprotected sex cuts the risk of developing syphilis, gonorrhea and chlamydia.
In June, the CDC started recommending doxycycline as a morning-after pill, specifically for gay and bisexual men and transgender women who recently had an STD diagnosis. But health departments and organizations in some cities had been giving the pills to people for a couple years.
Some experts believe that the 2022 mpox outbreak — which mainly hit gay and bisexual men — may have had a lingering effect on sexual behavior in 2023, or at least on people’s willingness to get tested when strange sores appeared.
Another factor may have been an increase in the number of health workers testing people for infections, doing contact tracing and connecting people to treatment. Congress gave $1.2 billion to expand the workforce over five years, including $600 million to states, cities and territories that get STD prevention funding from CDC.
Last year had the “most activity with that funding throughout the U.S.,” said David Harvey, executive director of the National Coalition of STD Directors.
However, Congress ended the funds early as a part of last year’s debt ceiling deal, cutting off $400 million. Some people already have lost their jobs, said a spokeswoman for Harvey’s organization.
Still, Harvey said he had reasons for optimism, including the growing use of doxycycline and a push for at-home STD test kits.
Also, there are reasons to think the next presidential administration could get behind STD prevention. In 2019, then-President Donald Trump announced a campaign to “eliminate” the U.S. HIV epidemic by 2030. (Federal health officials later clarified that the actual goal was a huge reduction in new infections — fewer than 3,000 a year.)
There were nearly 32,000 new HIV infections in 2022, the CDC estimates. But a boost in public health funding for HIV could also also help bring down other sexually transmitted infections, experts said.
“When the government puts in resources, puts in money, we see declines in STDs,” Klausner said.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.
WASHINGTON (AP) — Scientists can’t know precisely when a volcano is about to erupt, but they can sometimes pick up telltale signs.
That happened two years ago with the world’s largest active volcano. About two months before Mauna Loa spewed rivers of glowing orange molten lava, geologists detected small earthquakes nearby and other signs, and they warned residents on Hawaii‘s Big Island.
Now a study of the volcano’s lava confirms their timeline for when the molten rock below was on the move.
“Volcanoes are tricky because we don’t get to watch directly what’s happening inside – we have to look for other signs,” said Erik Klemetti Gonzalez, a volcano expert at Denison University, who was not involved in the study.
Upswelling ground and increased earthquake activity near the volcano resulted from magma rising from lower levels of Earth’s crust to fill chambers beneath the volcano, said Kendra Lynn, a research geologist at the Hawaiian Volcano Observatory and co-author of a new study in Nature Communications.
When pressure was high enough, the magma broke through brittle surface rock and became lava – and the eruption began in late November 2022. Later, researchers collected samples of volcanic rock for analysis.
The chemical makeup of certain crystals within the lava indicated that around 70 days before the eruption, large quantities of molten rock had moved from around 1.9 miles (3 kilometers) to 3 miles (5 kilometers) under the summit to a mile (2 kilometers) or less beneath, the study found. This matched the timeline the geologists had observed with other signs.
The last time Mauna Loa erupted was in 1984. Most of the U.S. volcanoes that scientists consider to be active are found in Hawaii, Alaska and the West Coast.
Worldwide, around 585 volcanoes are considered active.
Scientists can’t predict eruptions, but they can make a “forecast,” said Ben Andrews, who heads the global volcano program at the Smithsonian Institution and who was not involved in the study.
Andrews compared volcano forecasts to weather forecasts – informed “probabilities” that an event will occur. And better data about the past behavior of specific volcanos can help researchers finetune forecasts of future activity, experts say.
(asterisk)We can look for similar patterns in the future and expect that there’s a higher probability of conditions for an eruption happening,” said Klemetti Gonzalez.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.
Waymo on Tuesday opened its robotaxi service to anyone who wants a ride around Los Angeles, marking another milestone in the evolution of self-driving car technology since the company began as a secret project at Google 15 years ago.
The expansion comes eight months after Waymo began offering rides in Los Angeles to a limited group of passengers chosen from a waiting list that had ballooned to more than 300,000 people. Now, anyone with the Waymo One smartphone app will be able to request a ride around an 80-square-mile (129-square-kilometer) territory spanning the second largest U.S. city.
After Waymo received approval from California regulators to charge for rides 15 months ago, the company initially chose to launch its operations in San Francisco before offering a limited service in Los Angeles.
Before deciding to compete against conventional ride-hailing pioneers Uber and Lyft in California, Waymo unleashed its robotaxis in Phoenix in 2020 and has been steadily extending the reach of its service in that Arizona city ever since.
Driverless rides are proving to be more than just a novelty. Waymo says it now transports more than 50,000 weekly passengers in its robotaxis, a volume of business numbers that helped the company recently raise $5.6 billion from its corporate parent Alphabet and a list of other investors that included venture capital firm Andreesen Horowitz and financial management firm T. Rowe Price.
“Our service has matured quickly and our riders are embracing the many benefits of fully autonomous driving,” Waymo co-CEO Tekedra Mawakana said in a blog post.
Despite its inroads, Waymo is still believed to be losing money. Although Alphabet doesn’t disclose Waymo’s financial results, the robotaxi is a major part of an “Other Bets” division that had suffered an operating loss of $3.3 billion through the first nine months of this year, down from a setback of $4.2 billion at the same time last year.
But Waymo has come a long way since Google began working on self-driving cars in 2009 as part of project “Chauffeur.” Since its 2016 spinoff from Google, Waymo has established itself as the clear leader in a robotaxi industry that’s getting more congested.
Electric auto pioneer Tesla is aiming to launch a rival “Cybercab” service by 2026, although its CEO Elon Musk said he hopes the company can get the required regulatory clearances to operate in Texas and California by next year.
Tesla’s projected timeline for competing against Waymo has been met with skepticism because Musk has made unfulfilled promises about the company’s self-driving car technology for nearly a decade.
Meanwhile, Waymo’s robotaxis have driven more than 20 million fully autonomous miles and provided more than 2 million rides to passengers without encountering a serious accident that resulted in its operations being sidelined.
That safety record is a stark contrast to one of its early rivals, Cruise, a robotaxi service owned by General Motors. Cruise’s California license was suspended last year after one of its driverless cars in San Francisco dragged a jaywalking pedestrian who had been struck by a different car driven by a human.
Cruise is now trying to rebound by joining forces with Uber to make some of its services available next year in U.S. cities that still haven’t been announced. But Waymo also has forged a similar alliance with Uber to dispatch its robotaxi in Atlanta and Austin, Texas next year.
Another robotaxi service, Amazon’s Zoox, is hoping to begin offering driverless rides to the general public in Las Vegas at some point next year before also launching in San Francisco.
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