New Delhi: People who are vaccinated against SARS-CoV-2, and have a certain history of psychiatric conditions, have an increased risk of contracting Covid-19, a new study has found. The finding may be related to impaired immune response and risky behaviours associated with some disorders. 


The study, led by researchers at the University of California, San Francisco (UCSF), was recently published in the journal JAMA Network Open. 


Patients Above 65 Yrs With Psychotic Disorders Have Increased Risk For Breakthrough Infections


The scientists observed that patients aged more than 65 with substance abuse, psychotic disorders, bipolar disorder, adjustment disorder and anxiety, faced heightened risks of up to 24 per cent for breakthrough Covid-19. In case of people aged less than 65, the risks for breakthrough Covid-19 were up to 11 per cent higher than for those without a psychiatric history. 


The data, for both age groups, was adjusted for age, sex, race, ethnicity and vaccine type, and for smoking and underlying conditions such as obesity, diabetes, cardiovascular, lung, kidney, and liver diseases.


The scientists obtained the data for more than a quarter of a million United States Department Veterans Affairs patients, who were fully vaccinated and had at least one test for SARS-CoV-2. 


According to the study, more than 50 per cent of the patients had received at least one psychiatric diagnosis within the last five years, and 14.8 per cent developed breakthrough Covid-19. 


Immunity Wanes More Quickly For People With Psychiatric Disorders 


In a statement issued by UCSF, Aoife O'Donovan, senior author of the study, said that the research suggests that increased breakthrough infections in people with psychiatric disorders cannot be entirely explained by socio-demographic factors or pre-existing conditions. She added that it is possible that immunity following vaccination wanes more quickly or more strongly for people with psychiatric disorders and they could have less protection against newer variants. 


According to previous research, led by UCSF scientists, people with heightened anxiety and probable post-traumatic stress disorder, and conditions associated with impulsivity, were more likely to engage in behaviours that put them at higher risk for Covid-19. 


As many as 2,63,697 participants were involved in the study, whose average age was 66. According to the study, 90.8 per cent of the participants were male. 


The participants with psychiatric disorders had a three per cent heightened risk for breakthrough Covid-19 infections in 2021, compared with the participants without a psychiatric history. 


However, the risk was 24 per cent higher for the participants aged more than 65 with substance abuse, 23 per cent higher for those with psychotic disorders, 16 per cent higher for those with bipolar disorder, 14 per cent higher for the participants with adjustment disorder, and 12 per cent higher for the patients with anxiety.


Why Were Some Younger Participants Less Likely Than Older People To Have Breakthrough Infections?


Even though there is a greater incidence of breakthrough infections among younger people, the study showed significantly smaller effects in the participants aged less than 65. 


For patients with psychotic disorders, the risks were 10 per cent lower compared to the older participants with a psychiatric diagnosis. O'Donovan attributed this decrease to possible lower socialisation among younger people with psychotic disorders compared with older people who "may be less socially isolated because of their greater burden of ill health and contacts with caregivers."


According to the study, the risks for breakthrough infections associated with substance abuse, adjustment disorder, anxiety, and post-traumatic stress disorder were higher in the younger participants than their peers without a psychiatric diagnosis. The risks for breakthrough infections were 11 per cent, nine per cent, four per cent, and three per cent for younger people with substance abuse, adjustment disorder, anxiety, and post-traumatic stress disorder, respectively.


Why Is There Higher Incidence Of Breakthrough Infection Among Older Participants?


According to Kristen Nishimi, the first author of the study, the higher incidence of breakthrough infection among older participants may be due to "decreased immunological response to vaccines that has been associated with some psychiatric disorders, which may be more substantial in older adults."


She noted that it is also possible that older adults with psychiatric disorders may require frequent in-person care, which could increase their interactions with the healthcare system.


Likelihood Of Breakthrough Infections In People With Non-Psychiatric Conditions


The scientists also calculated breakthrough risks for other non-psychiatric conditions, and adjusted them for factors like obesity and other underlying conditions. 


According to the study, the participants with chronic kidney disease had an increased risk of 23 per cent, compared with 20 per cent for HIV, 19 per cent for cardiovascular disease, 18 per cent for chronic obstructive pulmonary disease, and 13 per cent for sleep apnea. This is a serious sleep disorder in which breathing repeatedly stops and starts. 


O'Donovan said the results show that people with certain psychiatric conditions, particularly those aged above 65, face risks that are on par with other conditions. 


She added that mental health is important to consider in conjunction with other risk factors, and that some patients should be prioritised for boosters and other critical preventive efforts.