As of July 28, 2021, more than 195 million people have been infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide. This ribonucleic acid (RNA) virus, which is the cause of the coronavirus disease 2019 (COVID-19), has claimed more than 4.17 million lives around the world.
Study: Change in Symptoms and Immune Response in People with Post-Acute Sequelae of SARS-Cov-2 Infection (PASC) After SARS-Cov-2 Vaccination. Image Credit: Supavadee butradee / Shutterstock.com
*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
PASC
Between 10% and 30% 10% and 30% of individuals infected with SARS-CoV-2 have shown persistent symptoms. This group has been reported to undergo a chronic and post-infection disability, which has prevented many of them from returning to normal active life. At present, there is a lack of proper medical guidelines regarding clinical care for this group who are suffering from Post-Acute Sequelae of SARS-CoV-2 Infection (PASC).
Several recent studies have indicated that post complete vaccination, or even after receiving a single dose of the COVID-19 vaccine, individuals with PASC have experienced a reduction or complete elimination of their PASC symptoms. However, in other cases, the condition of these individuals worsened after vaccination. Taken together, there are many unanswered questions regarding the impact of vaccination on people with PASC, such as whether any particular vaccine changes PASC symptoms and the biological mechanism behind the improvement of their symptoms post-vaccination.
Survivor Corps and COVID-19
Survivor Corps is a COVID-19 patient advocacy organization consisting of over 170,000 members. Many of the members of this group have been infected with SARS-CoV-2 and are struggling with PASC symptoms. Survivor Corps has therefore been tracking patients who had been experiencing COVID-19 infection for a prolonged period throughout the pandemic.
The authors of the current study conducted their research through citizen science collaborations. The main aim of their research was to secure information about COVID-19 patients who had suffered a prolonged convalescence period.
Throughout the course of their study, Survivor Corps posted a poll to their patient community to inquire on the effect of vaccination on PASC symptoms. The researchers found that approximately 40% of candidates with PASC symptoms had shown a mild to complete cure of the existing symptoms after vaccination. However, around 14% of individuals reported worsening of their symptoms post-vaccination.
PASC has been observed among children who are 12 years of age and older. An interesting observation of this study was that women showed a more robust T-cell immune response as compared to men, who appeared to maintain a viral reservoir.
After analyzing this report, Dr. Akiko Iwasaki from Yale University independently developed and published hypotheses indicating why the vaccine affects people with PASC. She also explained what might be the reason for PASC in the individuals who showed improvement in their symptoms post-vaccination. Discussions between Survivor Corps and researchers at Yale had led to the decision to pursue the study further.
Hypothesis and study design
Scientists believe that understanding the mechanism behind the impact of vaccines on PASC symptoms would help develop an effective strategy to treat this group. A new study published on the preprint server medRxiv* focuses on the impact of vaccines on the changes in the symptoms in the PASC group.
The main objective of this ongoing study known as the Yale COVID Recovery Study is to assess the change in immune responses among individuals with PASC post-vaccination. The authors hypothesized that people with PASC show heterogeneity in their immune profile and viral reservoir.
Previous studies revealed that among the individuals with PASC symptoms and those who had been vaccinated, changes in the immune system were found to be connected with symptoms response. For example, people with autoreactive T cells benefit from effector function diversion by vaccine-induced cytokines. Additionally, post-vaccination, individuals with viral reservoirs may benefit from its elimination via antibodies and T-cells elicited by the vaccine.
This study also compared the immune profiles and viral loads of people showing PASC symptoms and with COVID-19 recovered patients without PASC. Here, the researchers used data from survey reports of the participants as well as immune analyses of samples provided by the participants.
As per the study design, four surveys will be conducted to monitor the symptoms profile of the candidates as well as their experience during the infection period. Further, blood and saliva samples from the candidates will be obtained three times during the study period.
The first biospecimen is to be collected at the time of enrollment, the second at six weeks post the first dose of COVID-19 vaccine, and the third collection will be carried out 12 weeks after the reception of the first dose of a COVID-19 vaccine. The survey and study enrollment will be conducted by REDCap at Yale, a platform that is associated with the collection of survey data from candidates in a user-friendly design setting.
Significance of this study
The authors of this study believe that the information collected from the participants via surveys and analysis of the biospecimens could provide a holistic account of the impact of the COVID-19 vaccine on the health and immune system of the recipients. Although the study results will be disseminated in the future, at present, the researchers have shared their surveys and study designs with other scientists who are currently studying PASC.
*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
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