The phrase "a decrease in the severity of" is correct and usable in written English.
It can be used when discussing a reduction in the intensity or seriousness of a condition, situation, or problem.
Example: "The new treatment has led to a decrease in the severity of the patient's symptoms."
Alternatives: "a reduction in the intensity of" or "a lessening of the seriousness of".
Prophylactic use of cabergoline has been associated with a decrease in the severity of ovarian hyperstimulation syndrome (OHSS).
Although the patient improved after treatment with adalimumab, a tumor necrosis factor-alpha (TNF-α) inhibitor, it was not specified whether an attempt was made to discontinue lithium in order to observe a decrease in the severity of the lesions.
Preliminary data suggest a decrease in the severity of malaria due to P. falciparum among those co-infected with intestinal helminthes [17].
Instead, increased self-management and perhaps a decrease in the severity of illness from certain pathogens may be responsible.
This reduction in AF-related hospitalizations was not simply due to fewer cardioversions, but also to a decrease in the severity of recurrent AF episodes.
The reduction in eating disorder features is largely mediated by a decrease in the severity of the interpersonal problem(s) targeted in treatment.
In their analysis, the researchers found that the participants reported an average 50-percent decrease in the severity of their anxiety and depression symptoms.
‐Decreases in the recurrence of NSCL/P in each of the following subgroups: Women with NSCL/P themselves Women with one or more children with NSCL/P ‐A decrease in the severity of NSCL/P in offspring of trial mothers.
He reported a decrease in the frequency and severity of MS attacks.
Concordant with a decrease in the incidence and severity of arthritis, antibody production to CII was significantly decreased (Table 2).
This was associated with a decrease in the symptoms and the severity of SCW-induced arthritis.
