Why is a third COVID-19 vaccine dose important for people who are immunocompromised?

by Dr Emily Edwards and Dr Kylie Quinn
Reproduced from The Conversation

Hear them discuss the topic on ABC radio (3 Sept)

A number of countries including the United States and the United Kingdom are moving to make a third dose of COVID-19 vaccine available to people who are immunocompromised.

But why are people with weaker immune systems at the front of the queue for a third dose?

Five ways our immune responses to COVID vaccines are unique

by Paul Gill and Menno van Zelm
Department of Immunology and Pathology
 excerpted from The Conversation 10 Sept 2020

The Oxford vaccine trial at the centre of safety concerns this week highlights the idea that people’s immune systems respond to vaccines differently.

Long-lived plasma cells are key to an effective vaccine

A plasma cell, situated in its survival niche, produces Y shaped antibodies.
Long-lived plasma cells are needed for successful vaccines as they can
produce anti-virus antibodies for decades. Image: Tarlinton lab

Long-lived plasma cells are needed for successful vaccines as they can produce anti-virus antibodies for decades. A recent study by Monash University immunologists is unpacking the factors contributing to successful survival of plasma cells.

In the wake of the COVID-19 outbreak, a lot of research is focused on developing a vaccine.  For a vaccine to be successful, it has to do two things. First, it must signal the body to generate a lot of plasma cells to make anti-virus antibodies. Second, these plasma cells have to live for years or even decades for the vaccination to work. However, the reality is that most of them only survive a few days.

Pushing the boundaries of vaccine research

L-R: Dr Kirsty Wilson, Honours student Julie Tran and Professor Magdalena Plebanski

by Anne Crawford

In 2010 Professor Magdalena Plebanski observed something that didn’t make sense to her as an immunologist; a nanoparticle made of polystyrene exposed to the lungs of mice was rendering the animal resistant to developing asthma.

But why would it? she asked.

The inert polystyrene particle did not cause inflammation, was non-toxic, safe and protected the mouse against the disease in a similar way to a vaccine. Conventional immunology with its antigens, T cells and antigen-specific responses, didn’t explain it.

Which type of polio vaccine is best?

By Dr Jodie Abramovitch

The current polio vaccine was developed by Albert Sabin in 1961 and is a live-attenuated, orally administered vaccine (OPV). Live-attenuated means that the polio virus is alive but unable to cause disease. In settings with high childhood mortality, the OPV is believed to have non-specific effects that allows for protection against other childhood infections such as paralytic poliomyelitis (also known as infantile paralysis caused by the polio virus), tuberculosis and measles. This non-specific protection is thought to be able to reduce mortality to infectious diseases, particularly in childhood, by up to 17%. The significance of this protection is controversial.

Professor Magda Plebanski

To reduce the incidence of poliomyelitis which is around 75 cases worldwide per year, the World Health Organisation (WHO) has recommended the OPV be replaced by an inactivated form (IPV) of the polio virus. Inactivated means the virus used in the vaccine is dead.

In a recent correspondence published in The Lancet, a group of physicians and scientists, including Professor Magdalena Plebanski from the Department of Immunology and Pathology, voiced their concern at a potential change to the form of the current polio vaccine from OPV to IPV. It was noted that previous evidence suggests that the IPV does not confer the same non-specific protection as the OPV. Therefore, the IPV may be associated with an increase in childhood mortality (caused by a range of different infectious diseases). The authors postulated that for every case of poliomyelitis that is reduced by the IPV about 4000 extra deaths due to other infectious diseases (resulting in 300 000 additional deaths each year) may occur that could have been prevented by the OPV.

The authors of this correspondence concluded by urging the WHO to conduct randomised trials of the two different forms of polio vaccine before phasing out the OPV. This would allow for a better understanding of the non-specific protection that each of the polio vaccines provides against other infectious diseases. The results of these trials would inform whether the IPV leads to a higher infectious disease mortality overall when compared to the OPV, as well as whether the OPV and IPV may be administered alongside one another in children to prevent poliomyelitis and keep infectious disease mortality low.

Reference: Fish EN, Flanagan KL, Furman D, Klein SL, Kollmann TR, Jeppesen DL, Levy O, Marchant A, Namachivayam S, Netea MG, Plebanski M,Rowland-Jones SL, Selin LK, Shann F, Whittle HC.  Changing oral vaccine to inactivated polio vaccine might increase mortality. Lancet. 2016 Mar; 387:1054-5.
doi: 10.1016/S0140-6736(16)00661-9.

Flu vaccine reduces risk of hospitalisation

By Dr Jodie Abramovitch

Professor Allen Cheng (left) and
Associate Professor Tom Kotsimbos (right)

Vaccination against influenza infection is recommended in high risk groups including the elderly, pregnant women and those with chronic illnesses. The flu vaccine is primarily aimed at reducing the severe health consequences of infection such as hospitalisation and death. However, most previous studies on the influenza vaccine were performed in healthy adults and have looked at protection against mild influenza infection rather than severe complications.

Designing a vaccine for ovarian cancer

By Dr Jodie Abramovitch

Ovarian cancer (OC) is the fifth most common cause of cancer-related death among women. Detection of OC is difficult with diagnosis often occurring at an advanced stage. Many women who have undergone conventional treatment, involving surgery and chemotherapy, have a poor prognosis for the 5 years post-treatment.

Past and present members of the Vaccine and Infectious Diseases
Laboratory. (L-R) Sue Xiang, Ying Ying Kong, Rohimah
Mohamud, Qian Gao, Kirsty Wilson, Mutsa Madondo,
Chindu Govindaraj, Magda Plebanski

Dr Sue Xiang and other members of the Vaccine and Infectious Diseases laboratory under Professor Magdalena Plebanski in the Department of Immunology and Pathology are working on developing an effective peptide-based vaccine for OC. Peptide vaccines can induce highly specific immune responses which limits adverse side effects. In two recent studies, they characterised peptides from the human Sp17 protein which is expressed abnormally in many OC cases.

Peanut allergy vaccine receives commercial funding boost

The AIRMed Allergy research group.
L-R Back row: Dr Jade Jaffar, Ms Jodie Abramovitch,
Dr Sara Prickett, Professor Robyn O'Hehir

L-R Front row: Ms Neeru Varese, Ms Kirsten Deckert,
E/Professor Jennifer Rolland, Ms Anita Hazard, Ms Tracy Phan

The effort to develop a vaccine that could change the lives of sufferers of peanut allergy has taken another step forward with the announcement of $4.85 million of further funding to support the Melbourne-based research.

The Director and Head of the Allergy, Immunology and Respiratory Medicine department in The Alfred and Monash University, Prof Robyn O'Hehir said peanut allergy is a rapidly growing problem in Australia and around the world.

This new investment from the Brandon Capital managed Medical Research Commercialisation Fund, together with the support of an additional $1.44M National Health and Medical Research Council grant (announced in November), will ensure Prof O'Hehir and her team at The Alfred and Monash University can continue the research effort that she began close to 15 years ago.

Understanding the design of effective particle-based vaccines against malaria

Malaria kills over half a million people
globally each year. Image: VectorBase

Malaria vaccine research has been ongoing since the 1980s with limited success. However, recent improvements in our understanding of the immune responses required to combat each stage of infection will allow for intelligent design of both antigens and their associated delivery vaccine vehicles/vectors. Synthetic carriers (also known as vectors) are usually particulate and have multiple properties, which can be varied to control how an associated vaccine interacts with the host, and consequently how the immune response develops.