Booster jab shows promise against Omicron – Expert Reaction

Preliminary lab results from Pfizer/BioNTech suggest a third booster dose of their mRNA vaccine may be able to stop the Omicron variant in its tracks.

According to their press release, people who had received a booster jab neutralised the Omicron variant to levels comparable to those observed for earlier variants after two doses.

The SMC asked experts to comment on the press release announcement.

Lesley Gray, Senior Lecturer, Department of Primary Health Care & General Practice, University of Otago, comments:

“The preliminary information from Pfizer show the benefit of having a third (booster) dose to significantly improve protection against the Omicron variant of COVID-19 is promising as Aotearoa New Zealand begins to roll out its booster programme for those vaccinated more than six months ago. It is still really important for people who have not yet had their first or second dose to please have those doses as soon as you are able to do so.

“Information so far relating to Omicron suggests much quicker and wider transmission, although it is not yet known whether this new variant poses a greater threat compared to other variants of COVID-19. Meanwhile, the Delta variant continues to deliver most severe illness for those not vaccinated or not yet fully vaccinated.”

 Conflict of interest statement: “Lesley is a named investigator on Health Research Council funded grants.”

Dr Dianne Sika-Paotonu, Immunologist, Associate Dean (Pacific), Head of University of Otago Wellington Pacific Office, and Senior Lecturer, Pathology & Molecular Medicine, University of Otago Wellington, comments:

“Preliminary data from Pfizer/BioNTech has just been released about vaccine-induced COVID-19 protection against the new Omicron variant of the SARS-CoV-2 virus.

“Results made available from an initial laboratory study have shown that the antibody levels generated after receiving three doses of the Pfizer-BioNTech COVID-19 vaccine can offer protection from the Omicron variant of the SARS-CoV-2 virus.

“Antibody levels generated in response to Omicron after just two doses of the Pfizer-BioNTech COVID-19 vaccine showed reduced immune protection.

“The antibody levels generated against Omicron after three Pfizer-BioNTech COVID-19 vaccine doses was comparable to the protection seen towards the wild-type and other variants of the SARS-CoV-2 virus after two Pfizer-BioNTech COVID-19 vaccine doses.

“The third Pfizer-BioNTech COVID-19 vaccine dose also showed stronger T cell immune responses were still generated, which is important as T cells are considered to indicate protection against severe COVID-19 disease.

“Although preliminary results, these findings indicate overall that two doses of the Pfizer-BioNTech COVID-19 vaccine still offers some protection against Omicron, however this protection can be improved with the addition of a third Pfizer-BioNTech COVID-19 vaccine dose.

“This supports the need for a third dose of the Pfizer-BioNTech COVID-19 vaccine in the form of a vaccine booster after the initial two doses in order to help protect against the Omicron variant.

“Importantly, more information is still needed about Omicron, and whether or not it causes more severe disease, hospitalisation and mortality when compared with the Delta variant of the SARS-CoV-2 virus.

“In the meantime, a maintained focus on vaccination, border controls and public health settings will be needed.

“We’re continuing to experience the impact of Delta, particularly for the most vulnerable in Aotearoa New Zealand. Please get vaccinated and tested, and reach out to help others do the same.”

No conflict of interest.

Dr Amanda Kvalsvig, Epidemiologist and Senior Research Fellow, Department of Public Health, University of Otago, Wellington, comments:

“The Covid-19 Protection Framework (‘Traffic Light System’) is designed around an assumption that a person with two doses of the Pfizer vaccine is fully vaccinated. Already, that assumption appears out of date. We’re now seeing evidence that we shouldn’t be considered fully vaccinated until we’ve had three doses. That’s concerning as we await the arrival of the Omicron variant in Aotearoa New Zealand. Keeping all our eggs in the vaccination basket is a high-risk strategy. To keep New Zealanders safe this summer and beyond we need layered protection that recognises the critical role of airborne transmission in this pandemic.

“First, as we prepare for the Auckland border to open, there needs to be strong public health messaging and support from Government for meeting up outdoors, keeping windows and doors open, and using ventilation and filtration systems in schools, workplaces, and other crowded indoor settings. New Zealand must now start to take masks seriously – we can’t afford to ignore this protection any longer. These measures will help to keep people safe over summer whether they’re fully vaccinated with three doses, partially vaccinated, or unvaccinated. This infection is controllable if we choose to control it.

“Second, we need a new Alert Level system to pick up the public health protections that are missing in the Traffic Light System. Earlier this year my colleagues and I published a proposal for an upgraded Alert Level system. This proposed system has several important protections hardwired into it including upholding Te Tiriti o Waitangi with Māori leadership, stopping airborne spread, and building system-level resourcing and support to protect those most at risk from impacts of the pandemic or its control measures.

“Third, we need to use this time well to prepare for winter. Without that layered approach to Covid-19 we face a difficult winter of dealing with colder weather, new Covid-19 variants, declining vaccine protection, and a potentially very high burden of flu and numerous other infections returning as the borders open. When it’s too cold to keep windows open, we’ll need to be able to monitor indoor air quality and optimise it using ventilation and filtration systems. Clean indoor air will be good for our health in so many ways, protecting us from Covid and many other infections, and helping people to stay alert and focused at work and school.

“Using this layered approach, we could not only stop Covid from spreading this summer, but potentially end the pandemic by cleaning up the air we breathe in the same way that cleaning up the water supply permanently stopped cholera epidemics in 19th century London. We shouldn’t be fatalistic – we have so many tools in the toolbox now.”

No conflict of interest.

Professor Nigel French, Co-Director, One Health Aotearoa, comments:

“This is encouraging news that underlines the importance of achieving as high as possible uptake of double vaccination, and an effective booster programme.

“The experimental work will need to be evaluated alongside real-world effectiveness as indicated by the company, which requires good surveillance data from around the world. Surveillance data will also enable us to address two other key questions: how transmissible is this variant? and how much severe disease will it cause?

“Whatever the outcome of this ongoing work, the key message is the same – vaccination, and all the other measures we are taking against the Delta variant, will help to limit any impact of Omicron on the population of Aotearoa New Zealand.”

No conflict of interest.

Professor Nikki Turner, Medical Director, Immunisation Advisory Centre, comments:

“Pfizer has recently released early information on its laboratory study of Omicron variant of SARS-CoV-2 in November.

“Preliminary data from this unpublished laboratory study suggests that there may be reduced effectiveness from the current vaccination formulation to the Omicron variant – particularly against mild disease.

“This laboratory study has identified reduced responsiveness to neutralising antibody titre for the Omicron variant. High levels of neutralising antibodies are important to prevent entry of the virus into the body, so reduction in levels is likely to particularly affect mild and asymptomatic disease.

“Therefore, these findings do suggest a likely reduction in vaccine effectiveness particularly for mild disease. However, immune response to disease also includes cellular protection (T-cell immunity) and an important finding noted by the Pfizer/BioNTech company is that T-cell immunity appears to remain highly protective after a two-dose course. This would suggest we can continue to expect reasonable protection to severe disease, which is a vital feature of an effective vaccine. This should continue to reassure us of the importance of continuing the heroic efforts of our vaccination programme to ensure as many of our population can access the vaccine as possible.

“A booster dose, or having previously had COVID, appears to be important in restoring much of the reduction in protection to the vaccine. There is a question as to when the best timing of a booster dose will be, many countries are considering what the best timing for a booster dose would be, and that is a decision that New Zealand is also currently reviewing.

“The important message is that we must continue to support as many New Zealanders as possible in receiving the primary course of vaccination followed by a booster dose. Further data will accumulate rapidly, allowing New Zealand to make a decision about the best timing of the booster dose that is expected to improve the protection for when we do see the Omicron strain in our community.”

Conflict of interest statement: “No conflicts of interest. NOTE: The Immunisation Advisory Centre (IMAC) has a contract with the Ministry of Health to deliver clinical advice, promotion, education and training to the healthcare sector for the national schedule vaccines and COVID-19 vaccines.”

The UK Science Media Centre has also gathered expert comments in response to this announcement. See all expert comments here.

Prof Eleanor Riley, Professor of Immunology and Infectious Disease, University of Edinburgh, comments:

“The press release from Pfizer provides reassuring information. Not only does a booster vaccination provide strong antibody-mediated neutralisation of Omicron but also the vast majority of the sites in the spike protein that activate T cells are conserved between Omicron and the vaccine strain. This suggests that a booster should provide high levels of protection against infection and severe disease.

“However, the data also show that two doses of vaccine are not sufficient to give high neutralising activity against variant viruses. This means that whilst two doses may be enough prevent severe disease they are not sufficient to control virus transmission.

“The message is clear: if we want to control virus transmission and avoid further restrictions, we need everyone who hasn’t yet done so to get vaccinated and to get their booster.”

No conflicts of interest.