People with cirrhosis of the liver may take
longer to achieve protection from SARS-CoV-2 and severe COVID-19 after
vaccination, according to large studies in the United States and Chile,
presented earlier this month at The Liver Meeting.
People with cirrhosis have weaker responses to many vaccines
due to immune dysregulation and research presented at the conference showed
that people with decompensated cirrhosis had especially weak responses to
vaccination with the Pfizer or Moderna SARS-CoV-2 vaccines.
However, there is limited information about the impact of
SARS-C0V-2 vaccination on the prevention of severe COVID-19 in people with
cirrhosis, as people with chronic liver disease were excluded from registration
studies of vaccines.
- compensated cirrhosis
The earlier stage of
cirrhosis, during which the liver is damaged but still able to perform most of
its functions. See also ‘cirrhosis’ and ‘decompensated cirrhosis’.
- decompensated cirrhosis
The later stage of
cirrhosis, during which the liver cannot perform some vital functions and
complications occur. See also ‘cirrhosis’ and ‘compensated cirrhosis’.
Two large studies reported on the clinical impact of vaccination
in people with cirrhosis.
Binu V. John of University of Miami Miller School of
Medicine presented the findings of an analysis of the Veterans Outcomes and
Costs Associated with Liver disease (VOCAL) cohort, which tracks approximately
120,000 US military veterans with cirrhosis receiving care through the VA
The study findings were also published in the October
edition of JAMA Internal Medicine.
The study investigated vaccine protection against infection
and severe illness by tracking four outcomes: a positive SARS-CoV-2 PCR test 28
days after the first vaccine dose, a positive PCR result 7 days after the
second vaccine dose, and hospitalisation or death due to COVID-19 28 days after the first dose and
7 days after the second dose.
The study matched recipients of the Pfizer or Moderna vaccines
with controls by date of vaccination, age, sex, race, ethnicity, co-morbidities,
alcoholic liver disease status and Child-Pugh score.
The published analysis included people with cirrhosis who
received the Pfizer or Moderna vaccine up to 17 March 2021, with no previous history
of COVID-19 or liver transplant. A total of 20,037 people were eligible for
inclusion in the analysis and matched with an unvaccinated control with
cirrhosis. (Of note, 34,184 people with cirrhosis remained unvaccinated by 17
March 2021, three months after vaccination began in the United States.)
Study participants were almost all male (97%), had a median
age of 67 years, 60% were White, 23% Black, 43% had alcohol-related cirrhosis,
34% were overweight and 34% were obese. Over half (52%) had diabetes and 31%
had three or more co-morbidities. Most had compensated cirrhosis (Child-Pugh
Class A, 84%) and the median MELD score was 8.
There was no significant difference in SARS-CoV-2 infection
up to 28 days after the first dose between vaccinated and unvaccinated
participants, but after the first 28 days, receipt of a first dose of either
vaccine was associated with a 64.8% reduction in infection. Seven days after
the second vaccine dose, receipt of either vaccine was associated with a 78.6%
reduction in the risk of infection.
Prior to 28 days after vaccination, the number
of hospitalisations was similar in the vaccinated and unvaccinated groups (28
vs 29). Receipt of a first dose of vaccine was associated with a 100% reduction
in the risk of hospitalisation or death due to COVID-19 from 28 days after
vaccination, as was a second dose.
When the analysis was restricted to the 3142 people with
decompensated cirrhosis, receipt of the first vaccine dose was associated with
a 50.3% reduction in the risk of infection more than 28 days after vaccination
and a 100% reduction in the risk of hospitalisation or death due to COVID-19. The
investigators say that this result needs to be confirmed in other populations
due to the low event rates for infections and hospitalisation (one infection in
the vaccinated group and two in the control group after 28 days, and one
hospitalisation in the control group).
In people with compensated cirrhosis, a first dose reduced
the risk of infection after 28 days by 66.8%.
The study investigators point out that lack of protection against
infection during the 28 days after the first dose contrasts with the higher
efficacy seen in clinical trials of the Pfizer and Moderna vaccines. They suggest
that people with cirrhosis may have impaired or delayed humoral immunity,
underlining the importance of maintaining strict preventive measures against
infection until the full vaccination course has been completed.