One in three people infected with the coronavirus has had Covid-like symptoms persist or recur for three to six months after diagnosis, a new study says, suggesting the so-called “long Covid” is afflicting more people than previously thought.
The study, led by University of Oxford scientists, used anonymized data from millions of electronic health records, primarily in the United States, to compare 273,618 patients with Covid-19 with 114,449 patients with influenza. The researchers looked at such symptoms as chest/throat pain, abnormal breathing, abdominal symptoms, fatigue, depression, headaches, cognitive dysfunction and muscle pain over a period of time.
It found that about 36% of Covid patients still reported disease symptoms three and six months after diagnosis. Most previous studies estimated the so-called long-haul Covid to afflict 10% to 30% of patients. The researchers also found that of those who had long COVID three to six months after diagnosis, roughly 40% had no record of such symptoms in the prior three months.
There was a higher incidence of long-Covid features in the elderly, in more severely affected patients, and in women, the study notes. But long-Covid features were also recorded in children and young adults, and in more than half of non-hospitalised patients, confirming that they occur even in young people and those who had a relatively mild illness.
They say: “The results confirm that a significant proportion of people, of all ages, can be affected by a range of symptoms and difficulties in the six months after Covid-19 infection,” said Dr. Max Taquet, who led the analysis at the University of Oxford. The findings were published in the journal PLOS Medicine
A Phase 3 safety and efficacy trial, conducted in the US, Chile and Peru, of AstraZeneca’s AZD1222 Covid-19 vaccine — which is available as Covishield in India — said the vaccine “was safe, with low incidences of serious and medically attended adverse events and adverse events of special interest” demonstrating an “overall estimated vaccine efficacy was 74.0%.”
The study, published in the New England Journal of Medicine, was conducted on more than 32,000 participants and found that in the age group of 65 years and above, the “estimated vaccine efficacy was 83.5%.”
The study, conducted between August 28, 2020 and January 15, 2021, reported that “119 serious adverse events occurred among 101 participants (0.5%)” who were administered the vaccine. In addition, “a total of 7 adverse events leading to death occurred in 7 participants in the AZD1222 group and 9 adverse events leading to 7 deaths occurred in the placebo group.”
However, the study does not attribute any of the deaths “to be related to the vaccine or placebo” and adds that while there were no deaths due to Covid-19 in the group administered the vaccine, there were two deaths due to the pandemic in the group that was given a placebo.
While it has been a long wait for AstraZeneca to get approval for use in the US, the company had in July said that rather than seeking emergency use authorisation, it would go in for a full approval from the USFDA. It is also exploring the possibility of supplying booster doses to people administered its own vaccine as well as those who have been administered either Pfizer-BioNTech’s or Moderna’s vaccine