Uncertainty has been surrounding the possible effect of Covid-19 vaccination, as no result of aftermath effect has been discovered.
A recent study published in the journal, Nature, showed vaccinated people in Israel are less likely to test positive for Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2) that causes COVID-19, however, a population-wide effect will take time to become clear.
Indeed as countries worldwide roll out COVID-19 vaccines, researchers are eagerly watching for early signs that they are having impact on the pandemic. Last week, researchers in Israel reported preliminary figures suggesting that people vaccinated there were about one-third less likely to test positive for SARS-CoV-2 than people who had not received a shot. But scientists say that population-wide effects of immunisation will take time to become clear.
Many factors will determine how soon scientists can detect the impact of vaccines on the pandemic. Among them are the extent of vaccine coverage, the effectiveness of shots at preventing disease and infection, and the rate of viral transmission.
According to Nature, the results from Israel are among the first to report the impact of vaccines administered to people outside clinical trials. They provide an early indication that the two-dose RNA-based vaccine developed by Pfizer–BioNTech can prevent infection or limit its duration in some vaccinated people.
In a preliminary analysis of 200,000 people older than 60 who received the vaccine, compared with a matched group of 200,000 who did not, researchers found that the chances of testing positive for the virus were 33 per cent lower two weeks after the first injection.
“We were happy to see this preliminary result that suggests a real-world impact in the approximate timing and direction we would have expected,” said Ran Balicer, an epidemiologist at Israel’s largest health-care provider, Clalit Health Services, in Tel Aviv. He expects to get more conclusive results several weeks after people receive their second shot.
Another analysis by Maccabi Healthcare Services found a similar trend, although neither study has been peer-reviewed.
Clinical trials of the Pfizer–BioNTech vaccine show it to be around 90 per cent effective at preventing COVID-19, and the preliminary data suggest it can also provide some protection from infection. But it will take longer to establish whether vaccinated people no longer spread the virus to unvaccinated people, said Balicer.
As more than 75 per cent of older people in Israel have been vaccinated, Balicer said he expects to see a drop in hospitalisations among vaccinated older people over the coming weeks.
However, most countries like Nigeria are prioritising COVID-19 vaccinations for people who have a high risk of getting severe disease and dying. So, the first evidence that shots are working in those countries will probably be reductions in hospitalisations, and then in deaths, said Alexandra Hogan, an infectious-disease modeller at Imperial College in London.
According to the study published in Nature, indirect effects
If vaccines are effective at preventing infections, then their indirect benefit — protecting unvaccinated people — will be visible only once enough people have been immunised.
The researchers said Israel would probably be the first country to see this kind of population-wide impact. This is because it is using a high-efficacy vaccine and aiming for wide coverage with the explicit goal of achieving herd immunity, when enough people are immune to a virus for its spread to be controlled.
In some places, the first signs of indirect protection might emerge in specific groups who have been widely vaccinated, such as health-care and long-term-care workers and their families.
Meanwhile, Pfizer and BioNTech have announced an advance purchase agreement with COVAX for up to 40 million doses of the Pfizer-BioNTech COVID-19 Vaccine. The doses will be delivered throughout 2021.
COVAX is a global initiative coordinated by the Global Alliance for Vaccines and Immunization (GAVI), the Coalition for Epidemic Preparedness Innovations (CEPI) and the World Health Organisation (WHO), to ensure equitable access to COVID-19 vaccines for all countries, regardless of income levels. COVAX includes an Advanced Market Commitment (AMC) financial mechanism that aims to ensure that 92 low- and lower-middle-income countries will be able to secure access to COVID-19 vaccines at the same time as higher-income countries.
The first doses are expected to be delivered in the first quarter of 2021, subject to the negotiation and execution of supply agreements under the COVAX Facility structure.
According to a joint press statement by the two firms, for the COVAX Advanced Market Commitment 92 countries, Pfizer and BioNTech will provide the vaccine to COVAX at a not-for-profit price.
"At Pfizer, we believe every person deserves to be seen, heard and cared for. That is why from the very beginning of our vaccine development program, Pfizer and BioNTech have been firmly committed to working toward equitable and affordable access of COVID-19 vaccines for people around the world,” said Pfizer Chairman & CEO Albert Bourla. “We share the mission of COVAX and are proud to work together so that developing countries have the same access as the rest of the world, which will bring us another step closer to ending this global pandemic and proving that Science Will Win for everyone, everywhere.”
"SARS-CoV-2 does not differentiate between borders – a global pandemic requires comprehensive solutions and worldwide collaboration. COVAX is a truly global initiative and we are happy to support by making BNT162b2 available in many low- and lower-middle-income countries to help protect vulnerable people worldwide," said Ugur Sahin, M.D., CEO and Co-founder of BioNTech.
The urgent and equitable roll-out of vaccines is not just a moral imperative, it is also a strategic and economic imperative,” said Dr. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organisation.
"This agreement with Pfizer will enable COVAX to save lives, stabilize health systems and drive the global economic recovery."
"Today marks another milestone for COVAX: in addition to securing access to doses, we are now expecting the first deliveries of life-saving COVID-19 vaccines in Q1. This is not just significant for COVAX; it is a major step forward for equitable access to vaccines, and an essential part of the global effort to beat this pandemic. We will only be safe anywhere if we are safe everywhere,” said Dr. Seth Berkley, CEO of Gavi, the Vaccine Alliance, which leads COVAX procurement and delivery.
According to the press statement, as part of a broader strategy to support developing countries beyond the agreement with COVAX, Pfizer and BioNTech are committed to partnering with other global health stakeholders to provide expertise and resources that can strengthen healthcare systems where greater support may be needed to deploy COVID-19 vaccines. This includes analysing supply chains and piloting novel approaches in low-income countries to address transportation and storage challenges. Pfizer and BioNTech are also committed to coordinating with international agencies to support supply and distribution in refugee and other vulnerable populations.
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