The Illinois Department of Public Health has now linked more than 9,200 cases of coronavirus to five different variants of the virus, including nearly 6,200 cases of a strain that originated in the United Kingdom.
According to the latest data from IDPH, a total of 9,211 cases of the virus are now linked to variant strains of the illness.
By far the most prevalent of those strains is the Alpha strain. Formerly known as B.1.1.7, the strain has infected at least 6,187 residents in Illinois, according to officials.
The Alpha strain of the virus is thought to be more contagious than the original strain of the COVID virus, and is thought to potentially cause greater risk of hospitalization and death, according to the CDC.
Illinois is also seeing an uptick in cases connected to the Gamma strain of the virus. That strain, formerly known as P.1, has caused 2,405 cases of coronavirus in Illinois, and was originally discovered in Japan and Brazil, according to the CDC.
The Gamma strain is thought to be resistant to specific antibody treatments, according to the CDC, and has been largely responsible for an outbreak of the virus in Brazil.
Illinois officials also reported 517 cases of coronavirus linked to the Epsilon variant, which was first discovered in California. Another 102 cases of the virus are linked to the Beta variant, formerly known as B.1.351. That variant was originally observed in South Africa.
BEIJING Neighborhoods under strict lockdown. Thousands quarantined. Millions tested in mere days. Overseas arrivals locked up for weeks and sometimes months.
China has followed variations of that formula for dealing with the coronavirus for more than a year and a new outbreak suggests that they could be part of Chinese life for some time to come.
China appeared to get the coronavirus under control nearly a year ago. But hundreds of millions of Chinese people remain unvaccinated. New variants of the coronavirus have appeared, and questions remain about whether Chinas self-made vaccines can stop them.
The latest cases have been found in Guangzhou, capital of the southern province of Guangdong. The authorities have blamed the Delta variant, which has caused widespread loss of life in India.
The city tested practically its entire population of 18.7 million between Sunday and Tuesday, some of them for the second time. It has also put neighborhoods with a total of more than 180,000 residents into total lockdowns, with practically no one allowed out except for medical testing.
The early infections appear to have jumped from person to person at a cluster of eateries. Each infected person has infected more people than in any previous outbreak that China has confronted, Zhang Zhoubin, deputy director of the Guangzhou Center for Disease Control, said at a news conference.
The epidemic faced by Guangzhou this time is an unprecedented opponent, and it requires more resolute and decisive measures to deal with it, he said.
Test facilities in Guangzhou have been operating around the clock. Lines are long. Residents wake early to try to beat the rush, but still find delays.
Mandy Li, a longtime resident of the citys Liwan District, where most of the infections have occurred, said she set her alarm clock for 3:30 a.m. She still had to wait an hour.
In the queue, there was a family of three, she said. Some woke their kids to line up, and some had strollers. But everyone was cooperative and quiet, as we know some volunteers and medical workers worked very hard and theyve been there all this time without rest.
Chinas approach has evolved since the coronavirus first emerged, when Beijing initially put harsh restrictions on hundreds of millions of people. Today its lockdowns are focused on neighborhoods rather than cities or provinces. China has made vaccination the centerpiece of its strategy.
Still, many of the core tenets remain for a huge and densely populated country: vast testing, strict limits on movement and intense scrutiny of arrivals from other countries.
Foreign businesses have worried that those limits on international travelers could snarl their plans. A European Union Chamber of Commerce survey released this week found that three-quarters of member companies said they had been adversely affected by travel restrictions, usually by hindering them from bringing in key engineers or executives.
Beijing has demanded that travelers from dozens of countries spend two weeks in employer-supervised quarantine even before flying to China. Once there, travelers must spend at least two weeks and sometimes three or longer in government-supervised quarantine, even if they are fully vaccinated. Rounds of tests can turn up a possibly false positive, leading to more tests and additional days or weeks in isolation.
A German national who flew into Shanghai last month said that he had been sent to a hospital isolation room for three days because he tested positive for antibodies, which he attributed to taking a second vaccine dose 16 days earlier.
June 13, 2021, 1:23 p.m. ET
Nurses took his blood twice a day and performed six throat swabs, four nasal swabs and two anal swabs daily, said the German, who insisted on anonymity to avoid offending the authorities. The hospital room had no towels, no toilet paper and no television, and the bed was a steel plate with a thin mat, he said.
The German said that, after consistently testing negative for the virus, he was allowed to spend the remaining 11 days of isolation in a government-supervised quarantine center.
Many businesses expect that China may retain stringent travel restrictions through February, when Beijing will host the Winter Olympics, and possibly through autumn of next year, when the Chinese Communist Party will hold its party congress.
Many foreigners in China face a choice: If they leave to visit spouses, children and other family members elsewhere, they may be unable to re-enter the country later because of the pandemic restrictions.
There is absolutely a growing fatigue for a lot of the foreigners who are here, said Jacob Gunter, senior policy and communications manager at the European Union Chamber of Commerce in China.
At home, Chinas leaders are pushing its people to get vaccinated. It has administered about 800 million doses by the governments count, compared with 300 million administered in the United States. Yin Weidong, the chairman and chief executive of Sinovac Biotech, one of Chinas main vaccine manufacturers, told state television last Friday that Chinese regulators had approved the emergency use of vaccines in children as young as 3.
Still, administering 800 million doses almost all of the vaccines require two shots means most of Chinas 1.4 billion people have not been fully vaccinated. Some people remain hesitant to get the shots, and Chinese media outlets have used the Guangzhou outbreak to encourage skeptics to get inoculated.
The spread of the virus has raised fresh questions about the effectiveness of Chinas vaccines, particularly against variants. The Seychelles last month and now Mongolia in the past three weeks have both had large numbers of infections despite high vaccination rates. Both have used the Sinopharm vaccine from China, although the Seychelles also relied partly on AstraZeneca vaccines.
The Delta variant now circulating in Guangzhou has also shown the ability in other countries to infect some people who had already been vaccinated, a phenomenon known as vaccine escape. Research elsewhere has found that to be a particular problem for people who have received only a first injection of a two-jab vaccine and are then exposed to the Delta variant.
Researchers in Britain have found that receiving only the first of two shots of the Oxford-AstraZeneca or Pfizer-BioNTech vaccines may be only 30 percent effective in preventing infection with the Delta variant, said Raina MacIntyre, who heads the biosecurity program at the Kirby Institute of the University of New South Wales in Sydney, Australia.
After two doses, effectiveness appears to rise to 60 percent with the AstraZeneca vaccine and 88 percent with Pfizer-BioNTech. With the degree of vaccine escape there is with the Delta variant, you really do need people to be fully vaccinated, she said.
Mr. Yin, of Sinovac, told Chinas state-run television on Saturday that a third shot of his companys vaccine produces a tenfold increase in antibodies within a week. But Chinese vaccine manufacturers are not yet recommending a third dose.
As far as China is concerned, in fact, completing the two-shot immunization is the most important task for all the public, he said.
In the meantime, Guangzhou has tried to turn its virus setback into a showcase for local technologies. Officials there said they had used 31 driverless shuttle vans and trucks to send food and other critical supplies into locked down neighborhoods to avoid exposing delivery personnel.
By Tuesday, Guangdong Province had 157 people in hospital with the virus and was announcing about 10 new cases per day. The province and also Guangzhou itself have banned anyone since last weekend from leaving unless they have a valid reason and a negative nucleic acid test for the virus within the preceding 48 hours.
Unlike many places around the world, Guangzhou at least does not have to worry about running out of pandemic supplies: It is coincidentally a hub for manufacturing and exporting them. Chen Jianhua, chief economist of the Guangzhou Bureau of Industry and Information Technology, said at a news conference on Wednesday that the citys daily production capacity was 91 million masks and seven million sets of coronavirus detection chemicals.
Albee Zhang contributed research.
Over the past century, many notable viruses have emerged from animals to cause widespread illness and death in people. The list includes the pathogens behind pandemic influenza, Ebola, Zika, West Nile fever, SARSand now COVID, brought on by the virus SARS-CoV-2. For all of these microbes, the animal species that served as the original source of spillover was hard to find. And for many, that source still has not been conclusively identified. Confirming the circumstances and key participants involved in the early emergence of an infectious disease is a holy grail of this type of scientific inquiry: difficult to track and even more difficult to prove.
In ideal conditions, the first human cases involved in a zoonotic disease spillover (when a pathogen jumps from animals to humans) are reported in connection to animals present at the time of the event. This happens when the cluster of cases is large enough to be investigated and reported. But it is not necessarily the first time spillover occurred. Most spillovers are limited to more narrow animal-to-human cases. Once pathogens start to spread by human-to-human transmission, the tracks leading back to the initial animal source grow faint and become nearly impossible to follow.
Thus, animal sources for viruses that cause pandemics often remain shrouded in mystery. For some viruses, animal sources have been implicated after years or decades of large-scale international investigations. For other viruses, animal sources are highly suspected, but enough evidence has yet to be produced to pinpoint an exact species or range of species. Typically, lines of evidence are drawn over time through a trove of peer-reviewed publications, each building on the research that came before it, using more precise methods to narrow the field of possible sources. The scientific process is naturally self-correcting. Often seemingly contradictory hypotheses can initially flood the field, especially for high-impact outbreaks. But eventually, some of them are ruled out, and lines of investigation are narrowed.
Frequently, this investigative research only points to a group of suspected species, possibly a few most likely genera or, more often, an entire taxonomic order. That is because the virus has not actually been found in the suspected animal source in such cases. The evidence instead revolves around closely related viruses or their most recent common ancestors, based on inferred evolutionary history. If a virus was found in animal samples after the same pathogen caused widespread transmission among humans, it is possible that the virus spilled from humans back into animals. That happens often enough with viruses that can infect a range of animal species that the possibility needs to be presumed until it is ruled out.
The best way to rule out such spillback is to examine archives of specimens that were collected and stored prior to the initial outbreak. For these retrospective studies to work well, the specimens need to be the ideal type of samples, and they must come from the correct species and be stored in a way that allows scientists to recover the virus of interest.
Most viruses of interest typically infect animal hosts for only a matter of days. Detection of viruses that cause pandemics thus require sample sizes that are orders of magnitude higher than what is needed to detect endemic diseases or viruses that are long-lived in their host. One could get lucky, but rigor in scientific inquiry demands large sample sizes to power these types of analyses.
Investigations into an animal source that immediately follow a viral emergence event have an additional challenge. Because an outbreak in animals likely would have preceded the outbreak in humans, infections in animals would have already peaked. Few or none of them would still be infected. Immediately postoutbreak, the probability of identifying infection in live animals could be especially low, thus requiring even larger sample sizes. In China, it is not surprising that scientists did not find SARS-CoV-2 in potential animal sources immediately after the human outbreak in Wuhan. Nor does that result indicate there is a problem with the wildlife spillover theory. This is a difficult search that takes time.
Immunologic evidence of previous infection can be detected in a possible animal host in the form of antibodies, but new serological assays must be developed for a new virus. At best, this type of evidence is nondefinitiveand at worst, it leads us in the wrong direction in the hunt. Antibody responses to viruses are notoriously cross-reactive: the serological assays will react in the same way to related viruses, both known and as yet unrecognized. These assays must be evaluated and validated in every species, and there is no gold standard test for a new virus in a new animal. Any efforts to apply new tests to animals would need to be verified with repeated testing and supporting data.
As the scope of investigations broaden, other challenges must be met. Which species should be prioritized? Which locations should be investigated? Heading down the wrong path leads nowhere and wastes valuable time. Viral infections in animal populations are notoriously unpredictable, governed by dynamics that can only be uncovered with in-depth longitudinal studies after a virus has been found.
That brings us to the speed at which science works. Transdisciplinary collaborative research to investigate a novel virus takes extra time: detection techniques must be tailored to the new pathogen and customized to answer an array of research questions. Scientists are cautious about overinterpreting data and making unwarranted assumptions.And in the midst of a pandemic, understanding origins might not be the most pressing issue. During COVID, many scientists have pivoted to research that might help save lives this yearby modeling the trajectory of spread, characterizing SARS-CoV-2 variants and investigating the chances that the virus could spill back into different animals that serve as a new viral reservoir, ultimately threatening people again.
Timely exploration of the source of SARS-CoV-2 is important, but future pandemic preparedness requires a deep understanding of the mechanisms involved in the emergence of a much wider array of viruses with pandemic potential. With such knowledge, we will have better than a few vague and scattered clues the next time a novel disease emerges.
LA County coronavirus rules will ease this week, but experts say dont toss those masks just yet LA Daily News
Syracuse, N.Y. -- New York states rate of positive coronavirus tests continues to fall, reaching a new record low Saturday, the state reported.
The rate of positive tests dropped to 0.35%, the lowest single-day rate since the pandemic began. The seven-day positive rate was 0.42 yesterday. A news release from Gov. Andrew Cuomos office said that tied with Massachusetts for the lowest rate in the country.
Central New Yorks rate was higher, but still falling. Saturdays rate was 0.68%, down from 0.8% on Thursday.
A total of 110,437 tests were administered in New York state Saturday; 383 of them were positive.
The number of patients hospitalized fell by 51, to 630. Eight people died of Covid-19, the disease caused by the novel coronavirus. A total of 42,864 New Yorkers have died of Covid-19 since the pandemic began in early 2020.
Cuomos office said nearly 46,000 vaccine doses were administered Saturday, bringing the total so far to 20,061,871. Of New Yorkers 18 and older, 69.7% have had at least one vaccine dose.
About two-thirds of people eligible for inoculation against COVID-19 have now received two doses of the vaccine in Dubai, the tourist and business hub of the United Arab Emirates, Dubai Health Authority (DHA) said.
Dubai is the most populous of the seven emirates that make up the UAE and has one of the world's busiest airports.
For six months the UAE has been running one of the world's fastest vaccination campaigns against COVID-19, initially using a vaccine developed by the China National Pharmaceutical Group (Sinopharm) and then adding the Pfizer/BioNTech and AstraZeneca shots and Russia's Sputnik V.
DHA deputy director general Alawi Alsheikh Ali told Dubai Television late on Saturday that 83% of people aged over 16 - or about 2.3 million people - had now received at least one dose of a vaccine and that 64% had received two doses in the emirate.
The UAE recently said nearly 85% of its total eligible population had received at least one dose of a vaccine, without saying how many people had had both doses.
The UAE, which does not break down the number of cases by emirate, has seen a rise in the number of infections in the past month. It recorded 2,281 new cases on Saturday, bringing the total so far to around 596,000 cases. Daily cases peaked at almost 4,000 a day in early February.
DHA said 90% of the COVID-19 patients admitted to intensive care units in Dubai hospitals were unvaccinated, without specifying when that statistic was recorded.
Our Standards: The Thomson Reuters Trust Principles.
India on Saturday cut taxes on medical equipment such as oxygen concentrators and drugs used to treat COVID-19 infections, after widespread criticism over healthcare costs during a devastating second wave of the virus in April and May.
The government cut taxes on medical grade oxygen, ventilators, the remdesivir antiviral drug, diagnostic kits, pulse oximeters and hand sanitizers to 5% from 12-18% with immediate effect.
The new levies will be in place until the end of September, Finance Minister Nirmala Sitharaman said, adding it would include taxes on electric furnaces in crematoriums and ambulances.
"The rate cut has not be done with any cost implication (on government finances) in mind, it has been done so that people get some ease....the decision has been taken to provide ultimate ease to patients," Revenue Secretary Tarun Bajaj told a news conference.
The government, however, would continue to tax vaccines at 5%, he added.
The world's second-most populous country, where coronavirus cases hit a peak of 400,000 a day in May, reported 84,332 new infections on Saturday, the lowest in more than two months, data from the health ministry showed. There were 4,002 deaths.
The South Asian country's total COVID-19 cases stands at 29.4 million, with 367,081 fatalities.
During the second wave of the virus many people resorted to costly private treatment in what is still a low-income country.
Others paid twenty times the usual price for oxygen cylinders on the black market and huge sums to secure ambulances and hearses. read more
Experts have said millions of people remain vulnerable to new surges of infections, particularly in the countryside where two-thirds of the population lives.
Prime Minister Narendra Modi has said the government would take over the inoculation programme from Indian states and offer free doses to everyone over the age of 18.
The government would allow private hospitals to have 25% of all vaccine supplies, but not to charge more than 150 rupees ($2.06) over the cost of the dose, he said.
Our Standards: The Thomson Reuters Trust Principles.
Security personnel stand guard outside the Wuhan Institute of Virology in Wuhan as members of the ... [+] World Health Organization (WHO) team investigating the origins of the COVID-19 coronavirus make a visit to the institute in Wuhan in China's central Hubei province on February 3, 2021. (Photo by Hector RETAMAL / AFP) (Photo by HECTOR RETAMAL/AFP via Getty Images)
The lab leak hypothesis about the origin of Covid-19 has been getting a lot of attention lately, and deservedly so. This is the idea that the SARS-CoV-2 virus accidentally escaped from a laboratory in Wuhan, China, that conducts research on coronaviruses. Just a few weeks ago, a group of highly respected virologists and epidemiologists published a letter in the journal Science calling for a more thorough investigation, stating that the lab leak hypothesis was not taken seriously enough in earlier investigations.
The coincidence of having a major virus research facility, the Wuhan Institute of Virology (WIV), just a short distance from the live animal food market that was originally believed to be the source of the outbreak is too great to ignore. Even more curious is that WIV was actively doing research on coronaviruses in bats, including the bats that carry a strain of SARS-CoV-2 that is the closest known relative to the Covid-19 virus itself.
From the beginning of the outbreak, attention was focused on WIV, and various conspiracy theorists suggested, without any evidence, that the Covid-19 virus was either intentionally engineered, intentionally released, or both. Let me just say right off the bat that I dont believe either of those claims.
However, I do think the lab leak hypothesis is credible, and its also possible that gain of function research (more about this below) might be responsible.
In arguing against (unsupported) claims that the Chinese released the virus on purpose, a group of virologists published a paper very early in the pandemic, in March 2020, which looked at the genome sequence of the virus and concluded that SARS-CoV-2 is not a laboratory construct or a purposefully manipulated virus. Other studies since then have come to similar conclusions: the virus is very similar to naturally-occurring coronaviruses, and it is possible that it simply evolved naturally in the wild, probably in bats.
Even so, the lab leak hypothesis remains highly credible, regardless of whether or not the virus was genetically engineered. Heres why. First, we know that lab accidents can happen and viruses can escape, even if these accidents are rare. We also know that the Wuhan Institute of Virology had thousands of viruses, including coronaviruses, in its facility. And despite claims that viruses couldnt possibly have escaped accidentally, a 2017 Nature article describing the then-new Wuhan Institute reported, perhaps prophetically, that worries surround the [Wuhan Institute of Virology], too. The SARS virus has escaped from high-level containment facilities in Beijing multiple times.
The secrecy of the Chinese government, which has not yet allowed independent, outside scientists full access to WIV to investigate, hasnt helped matters. We need to know if any viruses in WIV are similar to the Covid-19 virus, and at this point we cant trust the Chinese governments assurances on this question. Of course, even if they allow outsiders to investigate now, we cannot know that they have preserved all the viruses that were present in the lab in the winter of 2019-2020.
Now lets talk about gain-of-function research. Gain of function, or GoF, refers to research that tries to make viruses or bacteria more harmful, by making them more infectious. This seems crazy, right? And yet its been going on for years, despite the efforts of many scientists to stop it. In the past, GoF research focused on the influenza virus, and in particular on a small number of scientists (highly irresponsible ones, in my view) who were trying to give avian influenzabird fluthe ability to jump from birds into humans. I wrote about this in 2013, and in 2017, and again in 2019, each time calling on the US government to stop funding this extremely dangerous work. The NIH did put a pause on gain-of-function research for a few years, but the work resumed in 2019.
Now, let me explain why GoF research does not require artificially engineering a virus. Viruses mutate very rapidly all by themselves, and RNA viruses like influenza and SARS-CoV-2 mutate even more rapidly than DNA viruses. So a GoF experiment doesnt need to engineer a virus to make it more infectious: instead, scientists can simply grow a few trillion viral particles, which is easy, and design experiments to select the ones that are more infectious. For example, some GoF research on bird flu simply sprays an aerosol mixture of viruses into a ferrets nose (influenza research often uses ferrets, since you cant ethically do this with people), and waits to see if the ferret comes down with the flu. If it does (and this has been done, successfully), the strain that succeeds now has a new function, because it can infect mammals. The viruses that are artificially selected (as opposed to natural selection) in these experiments will appear completely natural; no genetic engineering required.
We know that WIV was conducting gain-of-function experiments, and we know that its work included coronaviruses. Was the Wuhan Institute of Virology running GoF experiments on SARS-CoV-2 viruses from bats? Possibly. And if it was, these experiments could easily have produced a strain that infected humans. If a lab employee was accidentally infected with such a strain, that could have started the pandemic. And even if SARS-CoV-2 wasnt the subject of GoF experiments, a naturally-occurring strain being studied at WIV could still have infected one of their scientists and thereby leaked out into the population.
Im not saying that any of these events is likely. I am, however, agreeing with the scientists who, in their recent letter to Science, called for a deeper investigation into the cause of the Covid-19 pandemic.
Finally, let me echo a sentiment they expressed in their letter, which is best said by simply quoting them: in this time of unfortunate anti-Asian sentiment in some countries, we note that at the beginning of the pandemic, it was Chinese doctors, scientists, journalists, and citizens who shared with the world crucial information about the spread of the virusoften at great personal cost. Rather than seeking to cast blame, we need to uncover the origin of the Covid-19 pandemic, and any behaviors that led to it, as a means to help all societies prevent future pandemics.
'We've got to carry on the legacy': Franklin family grieves father, husband lost to COVID-19 The Tennessean
Initial data support giving a dose of AstraZenecas COVID-19 vaccine (left) followed by one of Pfizer and BioNTechs (right).
By Gretchen VogelJun. 9, 2021 , 11:00 AM
Sciences COVID-19 reporting is supported by the Heising-Simons Foundation.
Faced with short supplies of COVID-19 vaccines and unforeseen side effects, some countries have adopted an unproven strategy: switching shots midstream. Most authorized vaccines require two doses administered weeks or months apart, but Canada and several European countries are now recommending a different vaccine for the second dose in some patients. Early data suggest the approach, born of necessity, may actually be beneficial.
In three recent studies, researchers have found that following one dose of the vaccine made by AstraZeneca with a dose of the Pfizer-BioNTech vaccine produces strong immune responses, as measured by blood tests. Two of the studies even suggest the mixed vaccine response will be at least as protective as two doses of the Pfizer-BioNTech product, one of the most effective COVID-19 vaccines.
Only a few of the potential vaccine combinations have been tested. But if mixing vaccines proves safe and effective, it could speed the effort to protect billions of people. This possibility opens new perspectives for many countries, says Cristbal Belda-Iniesta, a clinical research specialist at the Carlos III Health Institute. Governments, for example, could immediately distribute new doses without worrying about setting aside second shots of specific vaccines to give people weeks or months later.
Europe and Canada have an added incentive. Millions of people there received an initial dose of the AstraZeneca vaccine before governments recommended younger age groups avoid it because of the risk of a rare clotting disorder. They were left wondering what to do next: Get a second dose or switch to a different vaccine?
In a Spanish study that Belda-Iniesta helped lead, 448 people who received a dose of the Pfizer-BioNTech vaccine 8 weeks after an initial AstraZeneca dose had few side effects and a robust antibody response 2 weeks after the second shot. All 129 blood samples tested could neutralize a noncoronavirus expressing spike, the SARS-CoV-2 surface protein key to infecting cells, he and colleagues reported last month on The Lancets preprint site.
Similarly, Leif Erik Sander, an infectious disease expert at the Charit University Hospital in Berlin, and colleagues found that 61 health care workers given the two vaccines in the same order, but 10 to 12 weeks apart, produced spike antibodies at levels comparable to a control group that received two doses of Pfizer-BioNTech at the standard 3-week interval, and had no increase in side effects. Even more encouraging, their T cells, which can boost the antibody response and also help rid the body of already infected cells, responded slightly better to spike than fully vaccinated Pfizer-BioNTech recipients. A team conducting a smaller study in Ulm, Germany, had comparable results. Both groups have posted preprints on the medRxiv server.
Two different vaccines may be more potent than either vaccine alone, says Dan Barouch of Beth Israel Deaconess Medical Center, who helped develop the one-dose COVID-19 vaccine made by Johnson & Johnson. It and the two-dose AstraZeneca vaccine use a nonreplicating adenovirus as a vector to introduce DNA coding for the spike protein of SARS-CoV-2 into the recipients cells. Vaccines from Pfizer-BioNTech and Moderna instead use messenger RNA (mRNA) coding for spike, which cells take up and use to make the protein.
Mixing the two types of vaccine may give the immune system multiple ways to recognize a pathogen. The mRNA vaccines are really, really good at inducing antibody responses, and the vector-based vaccines are better at triggering T cell responses, Sander says. Matthew Snape, a vaccine expert at the University of Oxford, agrees the combination vaccine results so far are promising but cautions they dont resolve whether any improvement in T cell response results from longer dose intervals rather than the mixing.
The recent studies are imperfect because they are not designed to assess actual protection against COVID-19. That would require following large groups receiving different vaccine combinations to see who gets infected and sick over many months. The antibody and T cell measurements the studies rely on are thought to correspond to real-life protection, but studies are ongoing to determine exactly how reliable these correlates are.
Still, the findings support recent policy changes. Spain has authorized the mixing of the two vaccines for people under age 60. Other countries that have put age limits on the AstraZeneca vaccine, including Canada, Germany, France, Norway, and Denmark, have made similar recommendations.
More data are expected in the coming weeks. Snape and colleagues are studying eight vaccine permutations in roughly 100 people each: a first dose of either AstraZeneca or the Pfizer-BioNTech vaccine, followed by a dose of either the same vaccine or the opposite, with intervals of either 4 or 12 weeks. The group reported in The Lancet last month that people who received the mRNA vaccine just 4 weeks after AstraZenecas suffered significantly more side effects than those who received two doses of the same vaccine; data on those subjects immune response are pending. The program has expanded to include second doses of Modernas mRNA vaccine and the Novavax vaccine, which delivers the spike protein directly.
As the world races to vaccinate as many people as possible against COVID-19, these combination studies could be one more weapon against the just really embarrassing inequality in global vaccine access, says Hugo van der Kuy, a clinical pharmacologist at Erasmus Medical Center. It will be important to also include vaccines widely used outside Europe, he says, such as those made by the Chinese companies Sinovac and Sinopharm, which rely on inactivated copies of SARS-CoV-2, and Russias Sputnik V, whose two doses each use a different adenovirus.Snape agrees. Mixing shots, he says, will be the reality for many countries around the world aiming to make best use of the vaccines available to them.
