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Receiving at least one dose of a COVID-19 vaccine before the first infection is strongly associated with a reduced risk of developing post-COVID-19 condition, commonly known as long COVID, finds a study published by The BMJ today (Nov. 22).
The findings, based on data for more than half a million Swedish adults, show that unvaccinated individuals were almost four times as likely to be diagnosed with long COVID than those who were vaccinated before first infection.
The researchers stress that causality cannot be directly inferred from this observational evidence, but say their results "highlight the importance of primary vaccination against COVID-19 to reduce the burden of post-COVID-19 condition in the population."
The effectiveness of COVID-19 vaccines against SARS-CoV-2 infection and severe complications of acute COVID-19 are already known, but their effectiveness against long COVID is less clear because most previous studies have relied on self-reported symptoms.
To address this, researchers investigated the effectiveness of primary COVID-19 vaccination (the first two doses and the first booster dose within the recommended schedule) against post-COVID-19 conditions using data from the SCIFI-PEARL project, a register-based study of the COVID-19 pandemic in Sweden.
Their findings are based on 589,722 adults (aged 18 and over) from the two largest regions of Sweden with a first COVID-19 infection registered between 27 December 2020 and 9 February 2022.
Individuals were followed from a first COVID-19 infection until a diagnosis of post-COVID-19 condition, vaccination, reinfection, death, emigration or end of follow-up (30 November 2022), whichever came first. The average follow-up was 129 days in the total study population (vaccinated: 197 days, not vaccinated: 112 days).
Individuals who had received at least one COVID-19 vaccine dose before infection were considered vaccinated.
A range of factors including age, sex, existing conditions, number of health care contacts during 2019, education level, employment status, and dominant virus variant at time of infection were also accounted for in the analysis.
Of 299,692 vaccinated individuals with COVID-19, 1,201 (0.4%) were diagnosed with post-COVID-19 condition during follow-up, compared with 4,118 (1.4%) of 290,030 unvaccinated individuals.
Those who received one or more COVID-19 vaccines before the first infection were 58% less likely to receive a diagnosis of post-COVID-19 condition than unvaccinated individuals.
And vaccine effectiveness increased with each successive dose before infection (a dose-response effect). For example, the first dose reduced the risk of post-COVID-19 condition by 21%, two doses by 59%, and three or more doses by 73%.
This is an observational study, which provides less conclusive evidence of causality, and the researchers point to several limitations such as limited data on post-COVID-19 condition symptoms and that the diagnosis code is not yet validated, the potential impact of reinfections on vaccine effectiveness, and expectations about the protective effect of vaccination.
However, this was a large, well-designed study based on high-quality, individual-level registry data with a low risk of self-reporting bias, suggesting that the results are robust.
As such, the authors conclude, "The results from this study highlight the importance of complete primary vaccination coverage against COVID-19, not only to reduce the risk of severe acute COVID-19 infection but also the burden of post-COVID-19 condition in the population."
These findings, combined with evidence from other studies, highlight the association between the immune system and the development of post-viral conditions, and underline the importance of timely vaccination during pandemics, say researchers in a linked editorial.
They call for continued investigation into the evolution of long-term residual symptoms of COVID-19 and other viral illnesses as well as steps to "improve the accuracy of recording both recovery and continued illness after infection, and in quantifying key family, social, financial, and economic outcomes."
"Such estimates are fundamental to unlocking the funding required for future research and increased investment in specialist clinical services offering treatment and rehabilitation to support patients with post-viral conditions," they conclude.
More information: COVID-19 vaccine effectiveness against post-COVID-19 condition among 589,722 individuals in Sweden: population based cohort study, The BMJ (2023). DOI: 10.1136/bmj-2023-076990
Journal information: British Medical Journal (BMJ)
Key Takeaways
The shingles vaccine used in the United States, called Shingrix, is more than 90% effective at preventing shingles.Since its only been FDA-approved since 2017, theres not an extensive amount of information about how long that effectiveness lasts. But research on the duration is emerging every year.
Shingles is a viral infection that causes a painful skin rash with blisters that can occur anywhere on the body, Sarath Nath, MD, an infectious disease expert and assistant professor at Stony Brook Medicine, told Verywell.
Its caused by varicella zoster virus (VZV), which is the same virus that causes chickenpox, Nath said. After a person recovers from chickenpox, the virus stays inactive in their body, however, it can reactivate years later, causing shingles.
One of the best ways to prevent shingles is to get vaccinated. If you get the Shingrix vaccine, heres how long its expected to provide protection and the factors that can impact its effectiveness over time.
About one in three people in the U.S. will develop shingles. An estimated 1 million people get the infection each year.
According to the Centers for Disease Control and Prevention (CDC), Shingrix offers about seven years of protection against shingles. A 2022 study with over 7,400 participants looked at vaccine recipients five to seven years after vaccination, demonstrating it was still about 91% effective.
A study published earlier this month in BMJ assessed the efficacy of an older shingles vaccine, Zostavax, which used a weakened live varicella zoster virus. The results showed effectiveness of the live shingles vaccine is the highest in the first year after a person receives the shot, but declines over time. Vaccine effectiveness waned to 50% in the second year, 27% in the eighth year, and 15% after 10 years.Zostavax is no longer used in the U.S. precisely because of its lower efficacy.
The Shingrix vaccine is a recombinant vaccine and doesnt use the live virus.
The recombinant vaccine has been here only for a few years, Nath said. It is likely that the Shingrix vaccine is effective for even longer than seven years, but we will need time to know.
Although the vaccines effectiveness may wane over time, Linda Yancey, MD, an infectious disease specialist at Memorial Hermann Health System in Houston, said that the vaccine does continue to provide protection against shingles.
All vaccines are most effective just after they have been given, Yancey told Verywell. There is no one answer to the question of how long a vaccine is effective. It is going to vary from person to person. Every patient is unique.
The CDC recommends adults aged 50 and older receive two doses of the Shingrix vaccine spaced two to six months apart. Those who are 19 years and older who have weakened immune systems because of disease or medication should also get two doses of the Shingrix vaccine.
If someone misses the second shot, they should start the two-shot series over again.
Vaccine effectiveness can decline over time for various reasons, Nath said. One of those factors is waning immunity, where the bodys initial response to the vaccine weakens over the years. In addition, certain viruses and bacteria might change or mutate over time, potentially making the vaccine less effective against newer strains.
Other factors like age, health conditions, and individual immune responses may also contribute to the gradual decrease in vaccine effectiveness, Yancey said. For instance, treatments like chemotherapy and immunosuppressants can weaken the immune system and lessen how much protection a vaccine can offer.
The biggest impediment to effectiveness, however, is age.
Vaccines work best in people with strong immune systems, Yancey said. A healthy 50-year-old will get good robust protection for a long time, an ill 89-year-old, less so. However, some protection is better than no protection, so there is no age cap on the vaccine.
At this time, there is no booster shot available or used for shingles.
This could change over time as we get more information on the duration of protection, Yancey said. Science is always moving forward.
While it is possible to contract shingles after getting vaccinated, Nath said the risk of getting shingles is much lower in people who have already been vaccinated.
If you experience any symptoms associated with shingles, including skin sensitivity, itching, tingling, rash, or blisters, contact your healthcare provider for a proper diagnosis. Your provider may prescribe antivirals like acyclovir to speed recovery, and analgesics to help alleviate symptoms.
Analgesics (pain killers) are often needed in patients with shingles and rarely we use steroids to decrease inflammation, Nath said.
Other treatment options may include:
The shingles vaccine has been found to be effective for seven to 10 years after the two-dose administration. There is no booster shot available for the shingles vaccine, but experts say that might change in the future. Contact your healthcare provider to see if youre eligible to receive the shingles vaccine.
A video on Facebook contains claims about the death rate from myocarditis after the Covid-19 vaccines. The claim is misleading and not backed up by the data.
Myocarditis is very rare after Covid vaccination, as we have written about before, and the rate after Covid infection itself is higher. False information about the Covid vaccines is common, and may lead to people making bad decisions about their health. We have written many times before on this issue, and specifically about myocarditis risk.
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The video has circulated on social media recently, with the oldest we could find being posted to YouTube over a year ago. It features audio apparently of a man talking to a pharmacist about his son, who he says has been admitted to hospital with myocarditis after receiving the Covid-19 vaccine. The audio contains a number of general claims about the vaccines and children.
The man says: So you know what the prognosis is? You know what it is? Possible death within five years. 20% of people with myocarditis die. It is a permanent damaged heart.
Claims about high death rates from myocarditis are common, with widely shared posts stating: Myocarditis has a 20% fatality rate after 2 years and a 50% fatality rate after 5 years.
A US healthcare education company StatPearls also gave a mortality rate of viral myocarditis of up to 20% at 1 year and 50% at 5 years, while acknowledging this varies depending on how severe the disease was at the time, among other factors. Full Fact contacted StatPearls for their source on this, and they told us the statement was incorrect and will be removed from the article.
Myocarditis is an inflammation of the muscular wall of the heart (the myocardium), most often caused by viral infection. Common symptoms include chest pain, fever and tiredness.
This may occur very rarely after the Pfizer and Moderna vaccines, although the risk of myocarditis following a Covid infection appears to be higher when looking at people of all ages. The benefits of vaccination for Covid-19 generally outweigh the risks for most people.
Official myocarditis incidence figuresthe number of cases over a given time period, usually a yearare hard to come by, as many cases are mild and so not reported.
This also complicates assessing the proportion of cases which are fatal (the mortality rate), as only more serious cases are known about. As a result this could lead to overestimates. Studies typically look at patients who have been admitted to hospital, which will be the more severe cases that cause enough symptoms that people seek help.
For example, a 2019 study of admissions to hospital in the NHS in England found a 4% all-cause mortality (death from any cause) for patients who were admitted to hospital with myocarditis between 1998 and 2017.
It can cause permanent damage but the majority of cases do not lead to this, so it would be wrong to suggest that all cases of myocarditis lead to a permanent damaged heart as the video does.
The UK Health Security Agency says that: myocarditis and pericarditis following vaccination is usually mild or stable and patients typically recover fully without medical treatment, and that the long-term impacts arent yet known.
The general rollout of the Covid vaccines in the UK was extended to children aged 12 and over in September 2021 and to younger children in April 2022, so its too early to have any reliable data on possible consequences of post-vaccine myocarditis. But early indications dont support the videos claim.
Dr Matt Oster, a paediatric cardiologist and medical officer at the US Centers for Disease Control and Prevention, told fact checkers at Reuters that Myocarditis after COVID-19 vaccine has less occurrence of heart failure and has a milder acute clinical course and that short-term outcomes of myocarditis after COVID-19 vaccine are much better than those of typical viral myocarditis, with long-term outcomes being researched.
The general Covid vaccination scheme has been wound down in the UK, but seasonal boosters are available to those at increased risk.
Featured image courtesy of Alaa Najjar
NEW DELHI: Amid reports of challenges in Army recruitment, former service members of US Army, who were removed from the service after they refused to take the COVID-19 vaccine have now received letters from the US Army. The letter informs them that they have the option to request corrections to their discharge records. The letter has been circulating on social media notified former members of "new Army guidance regarding the correction of military records for former members of the Army following the rescission of the COVID-19 vaccination requirement." It is signed by Brigadier General Hope C Rampy, of the U. Army Director of the Military Personnel Management Office of the Deputy Chief of Staff The letter states, "as a result of the rescission of all current COVID-19 vaccination requirements, former Soldiers who were involuntarily separated for refusal to receive the COVID-19 vaccination may request a correction of their military records from either or both the Army Discharge Review Board (ADRB) or the Army Board for Correction of Military Records (ABCMR)." As per the letter, "individuals can request a correction to military personnel records, including regarding the characterization of discharge." It further stated, "Individuals who desire to apply to return to service should contact their local Army, US Army Reserve (USAR) or Army National Guard (ARNG) recruiter for more information." However, an Army spokesperson clarified that the letter, dated November 1, does not specifically request former Army members, who were dismissed for refusing the COVID-19 vaccine, to return to service. Additional information on this matter was provided by the Army on Monday. Lieutenant Colonel Ruth Castro, Army spokesperson in an email to Fox News Digital wrote, "As part of the overall COVID mandate recession process mandated by Congress, the Army mailed the letters following Veterans Day weekend to approximately 1,900 individuals who had previously been separated for refusal to obey the mandatory COVID vaccination order. The letter provides information to former service members on how to request a correction of their military records." On October 3, the US Army unveiled a comprehensive transformation of its recruiting approach, highlighting the formidable challenges posed by "the most challenging recruiting environment in a generation" for the armed forces. During a press conference at the Pentagon, Secretary of the Army Christine Wormuth and Chief of Staff of the Army Randy George outlined significant changes in how the Army plans to identify and recruit talent. This involves expanding the focus beyond high schoolers to encompass a broader segment of the youth labor market and establishing "an increasingly permanent and specialized talent acquisition workforce." The officials revealed that the Army anticipates concluding fiscal year 2023 with nearly 55,000 recruiting contracts, including approximately 4,600 for the Armys Delayed Entry Program, covering recruits slated to ship in the 2024 fiscal year. Consequently, the Army asserted that it will achieve its end-strength goal of 452,000 for active-duty soldiers.
MEXICO CITY (AP) Four out of five people in Mexico who got influenza shots so far this year turned down the governments recommendation that they get Russian or Cuban COVID-19 boosters at the same time, officials said Tuesday.
Assistant Health Secretary Ruy Lpez Ridaura attributed the high refusal rate to people being reluctant to get two vaccines at the same time.
People have a certain reluctance to get simultaneous vaccinations, Lpez Ridaura said.
But the population eligible for flu and COVID-19 shots people over 60 and people with underlying health problems are considered high-risk, and Mexicans in those groups had extremely high take-up rates for Covid vaccines in 2021 and 2022, according to the Health Department.
Some people appear to simply distrust the Russian Sputnik and Cuban Abdala vaccines, both designed in 2020 for variants prevalent at the time.
It is an old antigen, it's as if they were going to give me an influenza vaccine from 2020, said Andreu Comas, a professor of medicine at the Autonomous University of San Luis Potosi. There are no studies regarding the effectiveness of both of these vaccines against the (current) variants.
Mexico has bought millions of doses of the Russian and Cuban vaccines. The original plan was to administer around 20 million shots, but only about 1.9 million people, or 9.5% of those eligible, have agreed to take them since the vaccination campaign started in mid-October.
In contrast, 10 million people got the influenza shot in the same period.
President Andrs Manuel Lpez Obrador has been a big supporter of Cuba, hiring Cuban doctors, buying vaccines and construction materials from Cuba and supplying oil to the island.
Meanwhile, Mexico has held up approval for Pfizer and Moderna COVID-19 boosters, both of which were designed to work against the COVID variants currently circulating. While those shots have been approved for use in the United States since September, they may not be available for Mexicans until 2024.
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Follow APs coverage of Latin America and the Caribbean at https://apnews.com/hub/latin-america
MEXICO CITY (AP) Four out of five people in Mexico who got influenza shots so far this year turned down the governments recommendation that they get Russian or Cuban COVID-19 boosters at the same time, officials said Tuesday.
Assistant Health Secretary Ruy Lpez Ridaura attributed the high refusal rate to people being reluctant to get two vaccines at the same time.
People have a certain reluctance to get simultaneous vaccinations, Lpez Ridaura said.
But the population eligible for flu and COVID-19 shots people over 60 and people with underlying health problems are considered high-risk, and Mexicans in those groups had extremely high take-up rates for Covid vaccines in 2021 and 2022, according to the Health Department.
Some people appear to simply distrust the Russian Sputnik and Cuban Abdala vaccines, both designed in 2020 for variants prevalent at the time.
It is an old antigen, its as if they were going to give me an influenza vaccine from 2020, said Andreu Comas, a professor of medicine at the Autonomous University of San Luis Potosi. There are no studies regarding the effectiveness of both of these vaccines against the (current) variants.
Mexico has bought millions of doses of the Russian and Cuban vaccines. The original plan was to administer around 20 million shots, but only about 1.9 million people, or 9.5% of those eligible, have agreed to take them since the vaccination campaign started in mid-October.
In contrast, 10 million people got the influenza shot in the same period.
President Andrs Manuel Lpez Obrador has been a big supporter of Cuba, hiring Cuban doctors, buying vaccines and construction materials from Cuba and supplying oil to the island.
Meanwhile, Mexico has held up approval for Pfizer and Moderna COVID-19 boosters, both of which were designed to work against the COVID variants currently circulating. While those shots have been approved for use in the United States since September, they may not be available for Mexicans until 2024.
Follow APs coverage of Latin America and the Caribbean at https://apnews.com/hub/latin-america
Bill Gates on Tuesday laughed off a conspiracy theory that suggests the Microsoft co-founder hatched an "evil plot" with Dr. Anthony Fauci to produce faulty vaccines and track Americans.
During an appearance on Trevor Noahs podcast "What Now?" Gates suggested that the "wild" combination of the COVID-19 pandemic and social media had created "insane" and "stunning" discourse, some of which alleged the tech billionaire was engaged in a global scheme to harm the human population.
Noah asked Gates whether these negative opinions had changed his "appetite" or ability to engage in philanthropic efforts successfully.
Gates responded by telling a story about a woman who came up to him on the streets of Seattle and began accusing him of implanting a tracker inside her body.
BILL GATES SAYS AI IS 'PRETTY DUMB' NOW, BUT PREDICTS EVERYONE WILL HAVE ROBOT 'AGENTS' WITHIN 5 YEARS
Microsoft co-founder Bill Gates. (Justin Tallis - WPA Pool/Getty Images)
"I looked at her, and I said, gosh, I really dont need to track you; Im sorry. Let me take the chip out of you," Gates said as he and Noah erupted in laughter.
He then addressed conspiracy theories that Gates worked with Fauci on vaccines to depopulate the earth, keep tabs on citizens and alter their DNA. He also appeared to reference "The Real Anthony Fauci" by presidential candidate Robert F. Kennedy Jr.
"The fact that a book that talks about Fauci and I having an evil plot, killing millions of children with vaccinesthe fact that could sell so well, you know, was just another surprise to me about human nature and how having an oversimplistic explanation about what was going on or the motivations, that was kind of shocking," Gates said.
He added that while he was not necessarily concerned about the attitude towards him personally, the attitude towards vaccines has been "damning."
BILL GATES, MARK ZUCKERBERG, OTHERS ARE BANKROLLING THE WOKE EDUCATION AGENDA, SAYS PARENTS GROUP
Former NIAID director Dr. Anthony Fauci. (SAUL LOEB/AFP via Getty Images)
"Getting kids to take things like the measles vaccine is super important in many countries. You know, thats the difference between life and death. So, the skepticism about vaccines or medicine is very high and thats making our health work a lot harder," Gates said.
Last May, Gates made similar comments in an interview with the BBC.
"You almost have to laugh because its so crazy," Gates said of conspiracies levied against him.
Gates has repeatedly denied conspiracies related to vaccination in media interviews, but a May 2020 YouGov/Yahoo poll found that almost one in three U.S. adults believe the microchipping theory.
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A year later, another YouGov poll found that one in five Americans believed the U.S. government was pushing COVID-19 vaccines to microchip people.
"I mean, do I really want to track people?" Gates said in the BBC interview. "I spend billions on vaccines; I dont make money on vaccines. Vaccines save lives, they dont cause death, so you have to say its a bit of a strange world where channels for that [theory] gain a lot of interest."
Fears over Covid super spreader events have led to renewed pleas for Aussies to get the latest vaccine booster as a new wave sweeps the country.
As teens travel far and wide for end-of-year festivities like Schoolies, it could lead to thousands being infected with a dreaded bout of the virus just as the Christmas holidays near. So what can we do to prevent it and should we be worried?
Experts are warning that Covid continues to pose a threat to Australians and that precautions should be taken to avoid infection.
A new vaccine will be available in Australia from December 11, with everyone being urged to get it. It will protect against the new EG.5 (Eris) and BA 2.86 (Pirola) variants.
Conversations about mask mandates have been reignited following WAs decision to make masks compulsory in high-risk settings such as hospitals.
Should I be worried?
Virologists were adamant that Covid would evolve into "nothing more than the common cold" but today that is simply not the case and continues to carry a threat, experts warn.
Professor Catherine Bennett, an epidemiologist at Deakin University told Yahoo that while our population-level immunity is helping us get through this wave in a safer way than we have [before]," we still have to remember that "people can become very unwell and we're still losing lives".
Dr Raina MacIntyre echoed this, saying there's an "enormous" amount of evidence around chronic long-term conditions caused by the virus.
"This is not just a virus that causes respiratory illness, it does that, but it also affects blood vessels, the heart, lungs and brain and a range of other organ systems," she told ABC Radio Melbourne.
"There are also good studies that show if you are reinfected, your risk of long Covid increases. And we know long Covid is already impacting workforces in the US and the UK," she added.
Read more: Is Covid still a thing?
One of the most controversial issues at the height of the pandemic was mask-wearing. So will there be renewed efforts to encourage people to wear masks on the cusp of another outbreak this holiday season? WA has already brought back mandates for face masks in hospitals.
Story continues
However, it's unlikely to affect the masses. Monash epidemiologist James Trauer said, "I don't think we need a mask mandate across the whole of society". Lockdowns are also unlikely Dr Paul Griffin, the director of infectious diseases at Mater Health in Brisbane, said. "But people should still remain careful," adds Trauer.
The advice is particularly true for those attending high-risk social events including Schoolies, or Leavers, with new fears such occasions may become superspreader events. While taking precautions is necessary, Trauer says, "I don't think we should have any restrictions that are applied across the whole of society" such as banning these events. "And I don't think there's any need to limit gathering numbers" he added.
"But we do need to take precautions when visiting friends and relatives who are vulnerable. Dont put them at risk," he added. This includes the elderly or people with other medical conditions.
A "significant change in the virus" is what's caused the current wave. "Each time the virus changes, the protection that we have from past infection and vaccination declines and that allows the virus to transmit more readily," Griffin told Yahoo.
Bennett agreed and said a new wave was "expected". Mostly because protection from immunity or vaccination "wanes over time". As for vaccinations, only a "very small percentage" of the population is up to date and most people haven't had a shot in the past six months, according to Professor Adrian Esterman, an expert in epidemiology at the University of South Australia.
That's a question a lot of people are asking at the moment, and in short, if people are eligible for a vaccine, I would just encourage them to go and get vaccinated," Trauer said.
The new vaccine, which will be available in Australia from December 11, differs from the ones weve had previously. Its monovalent and designed specifically to target the current EG.5 (Eris) and BA 2.86 (Pirola) variants. The most recent boosters were bivalent and tailored to protect against both the original strain of COVID-19 and the Omicron variant.
Those who had their 2023 vaccinations do not need to get jabbed again, but for people who are particularly vulnerable, if they haven't had their booster, "now is the time to think about it because it will give you your best protection through this second wave for the year," Bennett said.
"Vaccination remains our most important defence against Covid," Trauer added.
Other precautions that Esterman says are effective and encouraged include:
WA Health Minister Amber-Jade Sanderson on Schoolies or Leavers, "We know large events are higher risk when it comes to contracting and spreading the virus. Anyone returning from Leavers who feels unwell should please stay away from their grandparents and other vulnerable people in our community until their symptoms resolve".
The Australian Technical Advisory Group on Immunisation (ATAGI) said in a recent statement, "Available data suggests monovalent XBB vaccines provide modestly enhanced protection from severe disease compared to older vaccines".
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A first shipment of 331,200 doses of RTS,S vaccine landed in Cameroon Tuesday (Nov. 21).
The World Health Organization, the UN children's agency UNICEF and the Gavi vaccine alliance said in a joint statement Wednesday (Nov.22) that the delivery "[signaled] that scale-up of vaccination against malaria across the highest-risk areas on the African continent [would] begin shortly".
RTS,S is the first malaria vaccine recommended by the WHO.
The jab acts against plasmodium falciparumthe deadliest malaria parasite globally and the most prevalent in Africa.
It is administered in a four-dose schedule which begins at around the age of five months old.
Several African countries are finalizing preparations for malaria vaccine introduction into routine immunization programs, with the first doses set to be administered in January-March 2024.
A further 1.7 million doses are set for delivery to Burkina Faso, Liberia, Niger and Sierra Leone in the coming weeks.
The shipments signal that malaria vaccination is moving out of its pilot phase Since 2019, more than two million children have been jabbed in Ghana, Kenya and Malawi in a pilot phase, resulting in substantial reductions in severe malaria illness and hospitalizations. Africa accounted for approximately 95 percent of global malaria cases and 96 percent of related deaths from the mosquito-borne disease in 2021.
Global malaria deaths dipped slightly to 619,000 in 2021of which 77 percent were children aged under five. Meanwhile, global malaria cases rose slightly to 247 million.
Data collection, study population, variables, and outcomes
We used the TriNetX platform to access aggregated, de-identified electronic health records (EHR) of over 90 million patients from 56 HCOs across all 50 American states, covering diverse geographic, age, race, and ethnic groups (United States Collaborative Network)5. The MetroHealth System, Cleveland Ohio, Institutional Review Board (IRB) has determined that research using the de-identified and aggregated data from TriNetX as described in this study is not Human Subject Research and therefore IRB review was not required. We have previously used the TriNetX platform to study risk factors and outcomes of COVID-19 infection and vaccination14,15,16.
TriNetX data are collected from participating HCOs, primarily from EHR systems comprised of structured demographics, diagnoses, procedures, and medications but also from facts extracted from clinical documents using natural language processing17. TriNetX completes intensive data preprocessing to minimize missing values. The platform also maps data to a clinical model with consistent semantic meanings so that the data can be queried consistently regardless of the underlying data source. All covariates are either binary, categorical, or continuous. Missing sex values are represented as Unknown Sex, while missing data for race and ethnicity are represented as Unknown Race and Unknown Ethnicity, respectively. The data available in TriNetX go back decades, depending on the HCO, and are frequently updated (80% of data providers update their data in 1, 2, or 4-week intervals)18. For this study, the EHR data were queried and analyzed on October 8, 2023.
The primary analysis compared the hazard of IS in patients aged 65 years and over after Pfizer bivalent booster versus monovalent booster; the secondary analysis compared the hazard of IS in patients aged 65 years and over after Pfizer bivalent booster versus Moderna bivalent booster (Fig. 2). The exposure of interest was vaccination by either the Pfizer bivalent booster (Pfizer bivalent cohort), Moderna bivalent booster (Moderna bivalent cohort), or Pfizer/Moderna monovalent booster (monovalent cohort) prior to August 27, 2023, to ensure sufficient time for follow-up at 21 and 42 days (Fig. 2). Patients in the monovalent cohort were included beginning in August 2021, while those in the Pfizer and Moderna bivalent cohorts were included beginning in September 2022, as these time periods represent when the cohorts began receiving booster vaccines in TriNetX. Cohorts were matched by demographics (age, sex, race, ethnicity), COVID-19 infection, medical conditions that are risk factors for both IS and severe COVID-19 infection19,20, and adverse socioeconomic determinants of health (Table 1). Self-reported race and ethnicity data in TriNetX come from the clinical EHR systems of the contributing HCOs. TriNetX maps race and ethnicity data from its contributing HCOs to the following categories: (1) Race: Asian, American Indian or Alaskan Native, Black or African American, Native Hawaiian or Other, White, Unknown Race; and (2) Ethnicity: Hispanic or Latino, Not Hispanic or Latino, Unknown Ethnicity. The outcome of interest was an encounter diagnosis for IS in TriNetX at either 121 days or 2242 days after booster administration (Fig. 2). Details of clinical codes for covariates, exposures, and outcomes are described in Supplementary Table 2.
Cohort selection and design.
To compare the hazard of IS between the Pfizer bivalent and monovalent cohorts, as well as the Pfizer bivalent and Moderna bivalent cohorts, the cohorts were propensity-score matched (1:1 matching by nearest neighbor greedy matching algorithm with a caliper of 0.25 standard deviations) for the variables enumerated above. KaplanMeier survival analysis was used to estimate the probability of IS at 121 days or 2242 days after booster administration. The KaplanMeier analysis estimates the probability of an outcome at a respective time interval (daily time interval in this analysis). To account for the patients who exited the cohort during the analysis period, and therefore should not be included in the analysis, censoring was applied. Patients are censored when the last data point in the patients record is within the time interval of interest, or if the outcome of interest occurs after the index event but before the start of the time window21. The Cox proportional hazard assumption was tested using Schoenfeld residuals22. The TriNetX platform calculates HR and associated 95% CI using the R survival package v3.2-3. For generating HR, TriNetX sets robust=FALSE using the R survival package, which is a limitation of the TriNetX platform since it does not consider potential clustering of patients within HCOs or specific geolocations. All statistical tests were conducted in October 2023 within the TriNetX Analytics platform with significance set at p-value<0.05 (two-sided). A sub-analysis was conducted to compare the hazard of first-time IS between the Pfizer bivalent cohort and monovalent cohort, but not between the Pfizer bivalent cohort and Moderna bivalent cohort due to limited sample size.
