A nurse administers a booster at the Covid-19 Vaccination Clinic on 0 = April 6, 2022 in San Rafael, California.
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Vaccines against Covid, while strong against hospitalization and death, offer little protection against long-term Covid, according to a study published Wednesday in the journal Nature Medicine.
The results are disappointing, if not surprising, for researchers who once hoped that vaccination could significantly reduce the risk of prolonged Covid.
Compared with an unvaccinated individual, the risk of prolonged Covid in a fully vaccinated individual is reduced by only about 15 percent, the study found.
“Vaccines are great at what they’re for,” meaning they prevent hospitalization and death, said Dr. Ziyad Al-Ali, a clinical epidemiologist at the University of Washington in St. Louis and lead author of the study. But they “offer very modest protection against prolonged Covid,” he said.
Vaccines against Covid were developed at the beginning of the pandemic, long before doctors, scientists and patients learned of the existence of long-term Covid. They were never intended to protect against it, said Al-Ali, who is also head of research in VA St. Louis’ healthcare system. “We need to review them now that we know that the virus can have long-term consequences.”
Dr Greg Vanichkahorn, director of the Covid Activity Rehabilitation Program at the Mayo Clinic in Rochester, Minnesota, who was not involved in the new study, said the results were not “too surprising”.
“We know that most people with long-term Covid have not had severe infections,” he said.
The study examines national health data from the U.S. Department of Veterans Affairs and includes medical records of nearly 34,000 vaccinated people who had sudden Covid infections and more than 113,000 who were not vaccinated when they were infected with Covid in January 2021. Until October 2021, people are considered fully vaccinated if they have received two doses of Pfizer-BioNTech or Moderna vaccine or one dose of Johnson & Johnson vaccine.
The researchers followed up for six months after the infection to see if the patients had long-term symptoms. While protection against long-term Covid was generally relatively low, vaccines were more effective in preventing some of Covid’s most life-threatening symptoms: vaccination reduced the risk of lung disease by almost 50 percent and blood clotting disorders by 56 percent. those who have not been vaccinated.
Al-Ali noted that the outbreak does not mean that a person will develop Covid for long – only about 10 percent of outbreaks will lead to the condition – but with so many people infected, it still affects a large number of people.
The data did not show whether a person was reinforced, but al-Ali said he did not expect the reinforcement to make much of a difference with long-term Covid vaccines or options such as omicron.
Vanichkacharn agreed. “Unfortunately, I don’t think the reinforcement will do much to prevent long-term Covid with the vaccine,” he said. “We have a lot of patients with breakthrough infections who are vaccinated as much as possible. We also didn’t notice much difference between the long-term variants of Covid. ”
This does not mean that vaccines are not an important tool in the fight against the pandemic, experts say.
In particular, boosters offer the greatest protection against severe acute Covid and reduce the risk of complications, said Dr. Jason Mayley, director of the Critical Disease Survival Program and COVID-19 at Beth Israel Deaconess Medical Center in Boston.
But for a long time Covid they are not necessarily the solution. “I don’t believe vaccination is the key to eliminating the long Covid,” Al-Ali said. “We really need to think about extra layers to protect us from the long-term effects of this virus.”
New approaches to prevent prolonged Covid
Covid cases are on the rise again in the United States, driven by a subunit of omicron called BA.2.12.1, according to the Centers for Disease Control and Prevention. However, public health measures such as camouflage and social distancing have largely disappeared.
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Al-Ali said he did not blame the people for this.
“It’s not pragmatic to tell people to disguise themselves for the next 10 years,” he said. But this underscores the need to improve vaccines and treatments in a way that can offer protection against long-term Covid.
“Now that we have removed all these other public health measures, vaccines are really the only layer of protection we have,” al-Ali said. “This raises the question of what other prevention or treatments may be available. Can we set up these original vaccines to deal with long-term Covid, or do we need intranasal vaccines or other therapies in addition?
Intranasal vaccines, for example, could be better at preventing transmission than current vaccines, but this is an area that needs to be explored, he said.
Mali, who also did not participate in the study, said growing research shows that one of the main risk factors for long-term Covid is the level of the virus in the body during an acute infection. This suggests that early treatment with therapies, including antivirals, may help prevent prolonged Covid by keeping these virus levels low.
“Currently, antiviral drugs are approved for emergency use for patients who are at high risk for severe Covid-19, usually the elderly or people with compromised immune systems,” Mali said. There is also interest, he said, in investigating whether antiviral treatments could benefit long-term patients with Covid.
Both Al-Ali and Vanichkahorn agreed that more research was needed on long-term Covid. “We need long-term research specifically for long-term Covid so that specific therapies can be developed,” Vanichkahorn said.
But right now, he said, “the best way to not have fun with Covid is not to get Covid.”
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