Discussion
In order to compare the infection situation between the KTRs and the
non-KTRs groups, we conducted a case-control study. Because of the
sudden onset and rapid infection of COVID-19, we did not have enough
time to prepare for a prospective study. However, we collected a large
number of cases, which can also accurately explain the problem.
According to our results, there was no statistical difference in the age
and gender composition of the patients in the renal transplant group
compared with those in the non-transplant group. While there was a
difference in vaccination between the two groups, with the vaccination
rate in the general population being 67.2%, significantly higher than
in the renal transplant group (P < 0.05)(Table 1). The
difference in vaccination may be one of the reasons of the different
complications between the kidney transplant group and the general
population group, which also indicates the protective effect of
vaccination. As for the general population, the reason for the
complications of the non-KTRs group may be that our non-KTRs group is
not the general population in general sense, but the people who need to
be hospitalized after COVID-19 infection, which is the general
population relative to the transplant population. Therefore, our general
population group will also have complications.
According to early data from Spain (as of December 2019), it occurs
within 60 days after kidney transplantation 46% of patients infected
with COVID-19 died[20]. The early symptoms of the
solid organ transplantation recipients were concealed due to the use of
immunosuppressants, but the later disease progressed rapidly. For
example, the incidence of pneumonia, the proportion of transfer to
intensive care unit (ICU), and the mortality rate of the solid organ
transplantation recipients recipients were increased compared with other
COVID-19 infected patients [21]. Among
hospitalized recipients of KTRs, the risk of secondary acute kidney
injury and dyspnea is 3.78 times and 4.53 times higher than that of
normal individuals, respectively, indicating poor prognosis[22].
As shown in Figure 2, there was no difference in the incidence of fever
between the two groups, while the highest temperature and the number of
days of fever of the two groups are different. The average highest fever
temperature of the non-KTRs group is 38.87℃, slightly higher than that
in the KTRs group (38.87℃). There is also a difference in absolute
lymphocyte count between the two groups. The absolute lymphocyte count
of the kidney transplant population at admission and 7 days after
admission is lower than that of the general population, with a
statistically significant difference (P<0.001,
P<0.001). The lymphocyte count of the kidney transplant
population is also lower than that of the general population, and the
difference is statistically significant (P<001). This may be
related to the use of immunosuppressants by patients after
transplantation.
Due to the use of immunosuppressants, it is difficult for renal
transplant recipients to carry out immunotherapy for COVID-19 infection
and inflammatory reaction. Monovir is less effective compared to other
recommended antiviral drugs, so it is not a first-line recommended
medication for the general population. However, this drug is not as
effective as solid organ transplant recipients. There was no significant
interaction between the immunosuppressive drugs used by the recipient in
solid organ transplant recipients[13].
According to the Diagnosis and Treatment scheme of COVID-19 (Version X)
of China, the patients infected with Omicron were clinically classified
to mild, moderate, severe and critically ill. The first two types,
collectively referred to as ordinary patients, were recommended to stay
at home and take self isolation and monitoring. Whlie in terms of those
with high-risk factors, they were suggested to take antiviral treatment
as soon as possible. Most KTRs have 2-3 high-risk factors, which belong
to the category of high risk groups that exhibit severe or critically
severe conditions. So the antiviral treatment is crucial, as well as the
monitoring and maintenance of graft function[2].
Our results indicate that the use of intravenous corticosteroids is
significantly higher than that of the general population (42.8% vs
6.0%, p=0.000), and the use of small molecule drugs such as azivudine
and combination packaging of nimatevir/ritonavir tablets is also
significantly higher than that of the general population. The use of
monoclonal antibodies and gamma globulin is also higher than that of the
general population.
According to Table 2, the time from symptom onset to discharge in KTRs
is significantly longer than that of the general population, with
statistical significance (p=0.000). The incubation period of solid organ
transplant recipients infected with COVID-19 is 1-14 days, most of them
are 3-7 days, and the incubation period is infectious. At present, there
is no evidence showed that there is difference between the latency of
transplant patients and other COVID-19 infected patients[23]. Typically, the median detoxification period
for individuals infected with the Omicron variant is 11.3 days, while
for the solid organ transplant recipients, it is extended to 14
days[24].