Covid-19 Remains Harmful and Deadly Even Months After Infection
A surprisingly large portion of patients who have suffered from Covid-19 continue to experience concerning symptoms and complications months after their initial infection. Increasingly, this prolonged battle is becoming known as long Covid, and those who suffer from it have been dubbed long haulers. Covid-19 differs from most other respiratory viruses in the sense that a lingering version exists, and scientists are working to better understand this emerging condition.
A manuscript from a recent study accepted for publication in the journal Nature was published online April 22. This report, authored by epidemiologists Ziyad Al-Aly and colleagues, provides unique insight into not only the vast number of conditions associated with long Covid, but also the risk of developing such sequelae.
Investigators leveraged the U.S. Department of Veterans Affairs (VA) national health care database to acquire a broad range of health information from over 5 million patients. They note the VA system is the “largest nationally integrated health care delivery system in the U.S.”
The study looked at patients who survived Covid-19 beyond the first 30 days of illness and compared them to a control group of similar demographics and characteristics. After six months, a number of health-related factors were assessed in each group.
Researchers found that those who survived the first month of Covid-19 were at a 59% increased risk of death over the following 6 months. Over that half-year time frame, 14.4 per 1000 control patients died compared to nearly 22.8 per 1000 Covid patients. This equates to an estimated eight excess deaths per thousand individuals in the six months following illness.
Survivors of Covid-19 were also found to be at increased risk for a host of other medical conditions. They had over three times the risk of acute pulmonary embolism (a blood clot in the lungs). Their risk of anemia, sleep problems, and asthma, for example, increased by over 30%. Covid survivors were more likely to be prescribed antidepressants, anti-seizure medications, blood thinners, and medications to control abnormal heart rhythms.
Many of the conditions analyzed were even more likely to be present in patients who had required hospitalization for Covid-19. That risk was higher still for patients admitted to the intensive care unit (ICU).
The authors carefully designed the study to assess other control conditions that were considered unlikely to be associated with long Covid. These included the incidence of cancer and accidental injuries. As expected, these conditions were no more likely to develop in a Covid survivor than a patient who had never contracted Covid-19.
Furthermore, the study compared a group of patients hospitalized with influenza and those hospitalized with Covid-19. Even 30+ days after their initial diagnosis, those hospitalized with Covid-19 were 51% more likely to die within the next six months compared with those who had been hospitalized with influenza.
Unfortunately, the study doesn’t shed light on how Covid-19 produces such symptoms over the long-term. The authors note that long Covid could be explained by “several hypotheses including persistent virus in immune privileged sites, aberrant immune response, hyperactivation of the immune system, or autoimmunity.” They also comment that other nonbiologic factors could play a role — such as reduced social contact and loneliness, loss of employment, and changes in diet and exercise that may occur in patients who have suffered from Covid-19.
The study was also limited by the high percentage of VA patients who are male. The authors caution, “Our findings may not identify clinical features of post-acute Covid-19 that may be differentially much more pronounced in females.”
Because of the lack of robust data on long Covid, I harbored doubts about the seriousness of this condition. However, this study provides compelling evidence for the realities long haulers face. The authors explain that their study “highlights the need for holistic and integrated multidisciplinary long-term care of Covid-19 survivors.”
As the dynamics of the pandemic shift with the appearance of variants, development of vaccines, and improvements in treatment, the long-term effects of Covid-19 are likely to change as well. In order to keep up and care for my patients well, I’ll be on the lookout for further quality studies like this one.