US COVID vaccination program may have saved 279,000 lives
The US COVID-19 vaccination program may have saved almost 280,000 lives and prevented 1.25 million hospitalizations, according to the results of a modeling study published yesterday by the Commonwealth Fund.
The researchers already had a COVID-19 transmission model that took into account US demographics, age stratification and related COVID-19 risks, and pandemic mobility patterns, but to look at epidemiologic trajectories, they included variants of concern in addition to the original Wuhan, China–identified strain. Simulations ran from Oct 1, 2020, to Jun 28, 2021, and were validated with hospitalization rates and death trends.
The model showed that without the vaccination program, 279,000 more deaths, 1.25 million more hospitalizations, and 26 million more cases would have occurred. If the vaccination program had been half as fast, about 121,000 more deaths, 450,000 more hospitalizations, and 22 million more cases might have occurred.
While the difference in the number of prevented cases is smaller under the slower-rollout scenario, the researchers say this is most likely because of the vaccines' effectiveness in reducing severe disease and death.
The researchers note that if there had been no vaccination program, the country may have seen a second "2021 spring surge" of 4,500 daily deaths driven by the Alpha (B117) variant. This would have surpassed the 2021 winter surge, which peaked at 4,000 daily deaths.
"A renewed commitment to expanding vaccine access will be crucial to achieving higher levels of vaccination necessary to control of the pandemic and prevent avoidable suffering, particularly for those in historically underserved groups and areas of the U.S. with low vaccination rates," the researchers write. Of particular concern, they add, is the Delta variant (B1617.2), which may be more transmissible than Alpha and already makes up more than 40% of US cases.
Jul 7 Commonwealth Fund study
Heart rate might remain abnormal for 79 days during long COVID-19
For 234 COVID-19 patients, resting heart rates (RHRs) did not return to baseline until a mean of 79 days, reports a JAMA Network Open research letter yesterday. Step counts and sleep duration both took about a month to return to normal.
The researchers derived their COVID cohort from the Digital Engagement and Tracking for Early Control and Treatment (DETECT) study and analyzed data from Mar 25, 2020, to Jan 24, 2021. As a comparison, they also looked at 641 participants who had acute respiratory illness but not COVID-19.
COVID-19 patients had a mean age of 45.3 years, and 70.9% were women, whereas those without COVID-19 had a mean age of 44.7 years, and 71.1% were women. No information about severity of illnesses was given.
Overall, people diagnosed as having symptomatic COVID-19 took longer to return to their RHR, sleep, and activity baselines. The largest difference was seen in RHR, in which the researchers note that COVID-19 patients experienced a transient slow heartbeat followed by a prolonged relatively fast heartbeat, affecting RHR until a mean of 79 days post-symptom onset. Step counts and sleep durations were back to normal at 32 and 24 days, respectively.
Of the COVID-19 patients, 32 (13.7%) had a RHR more than 5 beats per minute above baseline that did not return to normal until more than 133 days post-symptom onset. This group also experienced more frequent symptoms than those whose RHR increased 0 to 5 beats per minute, including coughing, body aches, and shortness of breath during the acute phase.
"We found a prolonged physiological impact of COVID-19 infection, lasting approximately 2 to 3 months, on average, but with substantial intraindividual variability, which may reflect various levels of autonomic nervous system dysfunction or potentially ongoing inflammation," the researchers conclude.
Jul 7 JAMA Netw Open study
