New study looks at real world effectiveness of Covid-19 vaccines in solid organ transplant recipients

Posted on: 5th January 2022

New research, published in the scientific journal Transplantation, has looked at the effectiveness of the Pfizer and Oxford-Astra Zeneca vaccines for Covid-19 in solid organ and islet transplant recipients.  The research looked at the outcome of 40,000 UK patients who had a transplant comparing those who had received two doses of vaccine to those that were unvaccinated.

The study found that there was no evidence that the vaccine reduced the incidence of testing positive for Covid-19. However, it is important to emphasize that those who had two vaccine doses had a better chance of survival if they got COVID compared with those that were unvaccinated, with a 20% reduction in mortality.

Pamela Healy, Chief Executive of the British Liver Trust said, “We understand that these results will add to the worry that we know many liver transplant patients have been experiencing throughout this pandemic. We are all still learning about COVID-19, and in response to rapidly emerging scientific information, adjusting or introducing treatments where appropriate and possible. It is important for patients to remember that this is historical data and does not give us information about the efficacy of the third of fourth dose of the vaccine or about the Omicron variant.

"We advise that liver patients, particularly those with cirrhosis, those after a liver transplant, and those who have liver disease and are immunosuppressed get vaccinated."

The study also did not consider the behaviours of people after they were vaccinated. It’s important that people continue to follow other measures that reduce their risk such as social distancing, wearing face coverings and regular hand washing.

It’s also important that people within these higher risk groups with liver disease regularly test using lateral flow after potential contact and have a home PCR test available to allow early confirmation of infection.

New treatments available to NHS patients in these high risk categories that test PCR positive may reduce your risk of becoming sicker when used early in the course of COVID-19.

NHS Blood and Transplant have supplied the following answers to FAQs:

How many transplant patients were involved in this study?

We looked at the effectiveness of the two types of vaccine (Pfizer and Oxford Astra Zeneca) in 40,000 immunosuppressed patients. The UK is in a unique position where it can pull on information from multiple registries (UK Health Security Agency (UKHSA), which identifies patients testing positive for COVID-19, the National Immunisation Registry and NHS Blood and Transplant (NHSBT) Transplant Registry.

Why am I being advised to get a vaccine if it doesn’t work?

Vaccines in this immunosuppressed patient group are known, over many years, to be far trickier for all to manage. For instance, live vaccines (such as yellow fever) cannot be given to these patient groups and many vaccines, such as the Hepatitis vaccine, are known to be less effective at protection compared to the general population. But any benefit that a vaccine can offer will outweigh the risks of not being vaccinated at all. Two doses of COVID vaccines, does provide some protection against the worst consequences of this disease and it is likely that, just as in the general population, more doses will be better.

Why was I given Pfizer if AZ is better?

Clinical evidence from studies in the general population strongly indicates that two doses of both Pfizer and Astra Zeneca vaccines offer excellent protection from COVID-19. But in transplant patients, the published study indicates two doses of Astra Zeneca vaccine is more effective in protecting against death from COVID-19. The type of vaccine given to people was based on available evidence at the time as well as availability in their area.

Will booster vaccines really work in protecting me?

In the general population booster doses improve protection and it is likely similar protection will be seen in transplant patients. Vaccine effectiveness of a third or fourth doses in transplant patients is not yet known and research is on-going to answer this.

Why does AZ work better then Pfizer in transplant patients?

This is not something we have data on. Further research is needed.

What should I be doing to protect myself?

  • Take up the offer of 3rd and 4th vaccine doses as soon as they are available to you
  • Continue to practice non-medical/pharmaceutical interventions (NPI), including social distancing, wearing face coverings and regular hand washing
  • Encourage those you have close contact with to be fully vaccinated
  • If you develop symptoms suggestive of COVID-19, get tested as soon as possible
  • If you test positive for COVID-19 contact your transplant team as soon as possible for further advice

Will there be other studies to assess the effectiveness of a third and fourth dose?

We hope to report on a follow up study on third and fourth dose effects in summer 2022 and are collecting the required data right now.

When is best to get vaccinated?

Patients on the transplant waiting list are encouraged to get vaccinated as early as possible and complete the full course including booster doses prior to receiving their transplant. Transplant patients are encouraged to complete the full course including booster doses.

 

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