Association between Blood Type and Severity of Covid-19 Infection among Patients in Kaski District, Nepal

Novel Coronavirus (SARS-CoV-2) first broke out in China and speeded glo-bally. With the considerable number of Covid-19 infections and deaths, the situation has brought up major public health and governance concerns. This research study is conducted to understand if there is any association between blood group and Covid-19 disease severity. Study is conducted in Life care diagnostic and research center, New road Pokhara. A total of 1050 people who underwent RT-PCR test at Life Care Diagnostic and identified positive are used as the sample to conduct this research study. Our findings reveal that Covid-19 severity is uncommon in people with blood group O and Rh negative whereas those with blood group AB and B types are found to be severely affected. We also have an impression that individuals with rhesus negative (Rh-negative) blood groups have higher resistance for Covid-19 infection and severity.


Introduction
Covid-19 also called severe acute respiratory syndrome (SARS) is caused by SARS-CoV-2, a novel virus that belongs to the family Coronaviridae. Novel Coronavirus (SARS-CoV-2) was first reported in December 2019 in the Wuhan city, China [1]. On 31 st December, 2019, cases of pneumonia, an unknown etiol-How to cite this paper: Nagila, A.., Bhattrai, K., Koirala, R., Koirala, R. and Gauchan, P. In Nepal, the first Covid-19 case was confirmed on 23rd January, 2020 in a 31-year-old Nepali student who had returned from China. Similarly, the first death due to Covid-19 in Nepal occurred on 14th May, 2020 [4]. By the end of March 2021, Nepal had 277,461 Corona positive cases as registered and 3031 deaths occurred [5].
With increased number of illnesses and deaths associated with Covid-19, scientists are eager in presenting the data that characterized individuals susceptible to Covid-19 infection, and the risk factor that may be associated with disease progression and severity [6]. Many scholars and scientists from all over the world have been working relentlessly in finding the association between blood groups and SARS-CoV-2.
Article "Susceptibility to the novel coronavirus disease (Covid-19) is associated with ABO and Rh blood groups: a case-control study from Afghanistan" by Saify et al. took a sample of 301 Covid-19 confirmed cases in their study. The findings show that the blood group with RH− compared to the RH+ phenotype strongly increased the risk of Covid-19 (OR = 2.97, 95% CI 1.86 -3.89, p < 0.001). The study further reveals that O− vs O+ phenotype is significantly associated with the risk of Covid-19, which is quite similar to the association between Rh− and susceptibility to Covid-19 [7].
Likewise, "Association between blood type and Covid-19 infection, intubation, and death" by zietz et al. shows that type A blood was at decreased risk of intubation, and death compared to type O, while type AB was at increased risk of both outcomes. Additionally, type B individuals were at higher risk of intubation but at lower risk of death, compared with type O. Those with negative Rh (D) were at decreased risk for both intubation and death, consistent with a lower risk of initial infection [8].
In contrast to the above two findings, the study from MGH news and public affairs found that there is no relationship between Covid-19 and blood type. This study was done by Harvard Medical School researchers based at Massachusetts General Hospital. They included a study population of 1289 symptomatic adult patients positive for Covid-19 and document their blood group. The statistical analysis of the data determined that there is no correlation between blood type and intubation and/or death of the Covid-19 infected patients [9].
Though susceptibility of certain viral infections has been linked to antigenic determinants of ABO blood typing and severity of Covid-19 disease, the data from several studies remain inconsistent. This study aims to investigate the relationship between the blood group and risk of SARS-CoV-2 infection in 1050 covid-19 positive patients of Kaski district in Nepal. We hypothesize a link connecting ABO blood groups to SARS-CoV-2. We believe that this link will surely

Methods and Materials
The present study is carried out at Lifecare Diagnostics and Research Center in   Table 1 and Table 2 where Table 1 presented blood group and Covid-19 symptoms severity while Table 2 represented the chi-square expected value for blood group and symptoms severity.
We have our chi-square calculated > chi-square tabulated or chi-square critical value as presented in Table 3, calculation of chi-square.  For Individuals with comorbidities, we have excluded those sample from our study after identifying that certain blood group type (sample 100) are removed from the study. Those blood groups with associated comorbidities are listed in Table 4.
Populations having Covid-19 positive along with other comorbidities were identified and excluded from the study group to reduce the confounding factor (Graph 1 and Graph 2). Table 5 illustrates that people with B+ blood group are 67% more likely to have the risk of having Covid-19 symptoms severity compared to the other blood groups. We are 95% confident that the relative risk of having severe symptoms in B+ blood group compared to other blood groups is between 0.65 to 0.70. The null value is 1. Since the 95% confidence interval does not include the null value (RR = 1), the finding is statistically significant.

Discussion
It is crucial to better understand Covid-19, given the current pandemic's death toll. We investigated whether blood type is relevant for Covid-19 severity. Overall, we found modest but consistent differences between blood types and Co- was also provided to patients who were extremely fearful about the disease.

Limitation of the Study
The major limitation of the study is having small sample size and therefore could not generalize our findings. Moreover, the duration of the study is less than a year which is why we were unable to go back and follow up those participants.

Conclusion
This study found an association between blood type and Covid-19 disease severity. Majority of the population with blood group O+ were tested for Covid-19 through RT-PCR. Blood type B+ are found having severe Covid-19 symptoms. After blood group B+, the largest number of the population with A+ blood type was found having severe symptoms. Blood group O+, which was the highest number in the test, had only 6.95 percent of populations with severe symptoms. The present research study further found that there is a protective association between Rh-negative blood groups and SARS-CoV-2 infection. However, further study with bigger sample size and longer study duration is indeed vital for the generalization of the findings.