The information contained in this article is current, but it must be noted that COVID-19 vaccination is an evolving topic.

Even if they don’t have an underlying health condition, some people with COVID-19 can become very unwell and even need hospital treatment. Diseases of the immune system such as scleroderma, and medications used to treat these conditions, can potentially increase the risk from COVID-19. While some drugs such as dexamethasone have been shown to improve outcomes in those hospitalised with COVID-19 who need oxygen support, COVID-19 poses a serious threat and preventing infection is still the best strategy to combat COVID-19.

Through the efforts of scientists and researchers worldwide, Australians are now in a fortunate position to be offered vaccination against COVID-19, and already, millions of doses of vaccine have been administered, starting with high priority groups including those with pre-existing medical conditions. Two COVID-19 vaccines are currently available in Australia, but there will be others in the coming months. Neither of these vaccines contains virus that can replicate inside the body. Therefore, both are safe to be administered to people with underlying immune conditions or those on immune-suppressive medications. 

The Pfizer vaccine is developed using RNA technology. This supplies our cells with instructions on how to make the viral spike protein that functions as the ‘sticky tape’ that the virus uses to attach to our cells. The RNA instruction code teaches our immune system to make antibodies against the spike protein thereby preventing the virus from attaching to our cells. The Pfizer vaccine is safe and very efficacious in preventing COVID-19, but requires continuous refrigeration at a temperature of -70 Celsius. 

The Oxford (Astra Zeneca) vaccine is also developed using relatively new technology, but quite different to the Pfizer vaccine. It utilises a monkey adenovirus (a cold/flu-like virus) to carry the spike protein instruction codes into our cells. The monkey adenovirus is inactivated so that it cannot multiply in our cells and cannot make us sick. This makes it safe for people who do not have a fully functional immune system. The Oxford (Astra Zeneca) vaccine is also highly efficacious in preventing COVID-19 and needs only -4 Celsius refrigeration. 

Both vaccines require two doses to ensure maximum and long-lasting effectiveness, although some protection against COVID-19 is achieved as early as 10-14 days after the first dose. The optimal timing between the two doses depends on which vaccine is used, the availability of vaccine and the speed with which we need to fully vaccinate people. This means that some people may have two doses close together and others may have a longer interval between doses. The interval is governed by science and the circumstances at the time of vaccination.

Even though initial clinical trials showed that the Pfizer vaccine may prevent more COVID-19 infections than the Oxford (Astra Zeneca) vaccine, real world data indicate that the two are almost equally efficacious, around 80-90%, in preventing infection. The efficacy of both vaccines in preventing infection with the emergent highly infectious delta strain is around 70-80%. However, regardless of the strain, both vaccines are excellent in preventing serious illness and death. In the recent COVID-19 outbreak in NSW, almost all those who were admitted to intensive care or died from COVID-19 were unvaccinated, with a few being only partially vaccinated, having received only one dose of the vaccine. 

As with most vaccines, some people will experience mild side effects such as pain at the injection site (upper arm), fatigue, headache and muscle aches. Some may experience moderate side effects such as shivers and chills. Serious allergic reactions are extremely rare.

There are two possible side effects of COVID-19 vaccination that deserve specific mention. The Oxford (Astra Zeneca) vaccine carries a risk of vaccine-induced thrombosis and thrombocytopenia syndrome (VITTS), which is a condition of clotting in veins of the abdomen and veins surrounding the brain, sometimes associated with low platelet count resulting in bleeding and bruising. Fortunately, VITTS is rare, occurring with a frequency of around 8 per million in those under the age of 40. The risk of VITTS with the AZ vaccine diminishes with age, being around 0.4 per million in those over the age of 60 years. There are treatments now available for VITTS. The Pfizer vaccine is associated with a risk of myocarditis (inflammation of the heart), which is very rare but can occur in younger men. Most people with this condition recover. 

It is possible that in people who take medications that suppress the immune system as used to treat scleroderma, COVID-19 vaccines may not work as well due to reduced immune responses to the vaccine. However, the general recommendation is to continue on medications needed to treat scleroderma as without these medications, scleroderma can flare. As no vaccine can be guaranteed to prevent all infections, general measures to avoid exposure to COVID-19 remain important even after vaccination.

Presently, we do not know for how long these vaccines will confer immunity. It is conceivable that with time the vaccines will lose some of their protective effect as the virus mutates. Already, there is some evidence that the Oxford (Astra Zeneca) vaccine is less effective at preventing infection with the South African variant of the virus, although it still seems to protect people from serious disease. Therefore, it is possible that like influenza, we may need to have a booster vaccine each season. Ongoing studies around the world will shed more light on this in the coming months.

Other evolving areas include vaccination in children who appear to be more susceptible to infection with the delta strain than they were with the original virus, although the illness in children is still generally milder compared to adults. Even so, it is likely that in time children too will be immunised, to protect them and those around them. Clinical trials overseas have already confirmed the efficacy and safety of Pfizer vaccination in children aged 12 years and over, with trials now focussing on children under the age of 12 years.

In summary, both COVID-19 vaccines that are currently available in Australia are safe and highly efficacious in preventing COVID-19 infection, hospitalisation and death. All individuals with scleroderma who are aged 16 years and over are now eligible to receive immunisation. Current goals are to ease restrictions and consider ending lockdowns when 80% of our population is fully vaccinated. Therefore, to protect themselves and those around them, all people with scleroderma should consider vaccination, as the likely benefits far outweigh potential risks of immunisation.

If you have any questions about the specifics of your case and your suitability for vaccination, please discuss this with your GP or your Rheumatologist. 

A/Professor Mandana (Mandy) Nikpour Rheumatologist, St Vincent’s Hospital Melbourne – Chair, Australian Scleroderma Interest Group

Professor Marc Pellegrini, Infectious Disease Physician. Joint Division Head, Infectious Diseases and Immune Defence,  The Walter and Eliza Hall Institute of Medical Research (WEHI)

August 31, 2021