They can be combined with the seasonal flu shot or come in the form of pills or patches instead of vaccines. Scientists are also considering vaccines that could protect against viruses beyond SARS-CoV-2 (the virus that causes COVID-19) that could prevent future pandemics.
And they’re evaluating whether those who are fully vaccinated might need booster shots later this year. Further injections could be virtually identical to the first doses, given as a guarantee against the possibility of diminished immunity or adjusted to defend against mutant strains that raise concerns.
Here’s what we know about the next-generation coronavirus vaccine landscape:
The three major vaccine makers with injections licensed in the United States, Pfizer, Moderna and Johnson & Johnson, have plans for – or are already testing – an additional injection. The booster shots are expected to be very similar to current vaccines, but could come in a smaller dose.
“With many vaccines, we understand that at some point we have to increase, whether it’s 9 months, 12 months. And we are preparing for it, ”Dr David Kessler, scientific director of the administration’s response to COVID-19, told lawmakers.
Boosters can also be mixed with the annual seasonal flu vaccine. Moderna said he plans to pre-test such combination plans this year. Other combinations of vaccines are already frequently used to immunize young children against multiple diseases during a single visit to the doctor.
However, administration officials say no decision has yet been made on how the booster injections would be used – or whether they would even be needed.
What about the variants?
As the booster shots renew the body’s immunity to the virus by mimicking parts of the original strain first identified in China, vaccine makers are also trying to adjust their doses to treat the newer variants of the virus. SARS-CoV-2, some of which spread faster and can cause more serious illness.
It is not unusual; seasonal influenza vaccines are regularly modified to combat mutations spotted in the virus around the world.
Dr. John Mascola, head of the Center for Vaccine Research at the National Institute of Allergy and Infectious Diseases, says understanding SARS-CoV-2 mutations is “a major goal” for federal scientists.
The NIH has dedicated funds and researchers from across its campus to answering key questions about variations in the virus. Some scientists are focusing on testing the impact of mutations on vaccine effectiveness. Others are working to better understand and map its “epitopes,” places where antibodies can target the SARS-CoV-2 signature spike protein.
“It’s sort of a body of basic scientific knowledge that, in the long term, can guide antibody therapies, but also guide vaccine design. Basically say, ‘Can I understand how the virus is going to escape and can I explain that?’ Mascola explained.
Moderna and Pfizer are both researching possible versions of their adjusted doses for the B.1.351 variant first spotted in South Africa, although research so far suggests their current vaccines may remain primarily effective against the mutant. The AstraZeneca-Oxford vaccine, which is not authorized for use in the United States, has been shown to provide onlyagainst the South African variant.
“The reason they’re choosing this strain is because it’s one that we know about right now, with the worrisome variants that exist, it’s the most antigenically different,” Mascola said.
Mascola also raised the possibility that developing a booster with the South African variant could offer more protection.
“For example, if we reinforce with strain B.1.351 and see that the serum antibodies are larger, not only neutralizes the original strain but also B.1.351 and other variants, then that may be a problem. preferred approach, ”added Mascola.
Skip the needle
A substantial effort is also underway to offer vaccines that do not depend on needles and syringes to be administered, after record demand has strained the complex global supply chain amid the pandemic. Some projects could make it easier to store and transport the vaccine, without the expensive freezers and dry ice currently required for Moderna and Pfizer vaccines.
For example, future doses could be inhaled through the nose instead of being pulled into the arms. The NIH recently touted the promising results of a single-dose intranasal vaccine tested in monkeys, similar to that of AstraZeneca.
Last year, the Biomedical Advanced Research and Development Authority (BARDA) also announced millions of dollars in contracts to develop a handful of other alternatives delivered by wearable patches or pills, deploying the agency’s experts to developers through early testing and regulatory approvals.
Vaxess Technologies claims its self-applied patch is stable and painless, delivering its vaccine through microscopic “splashes” that dissolve into the skin.
“We are working with companies, with different technologies, to potentially link them to the six vaccine candidates that are currently supported by the US government,” said Gary Disbrow, director of BARDA.
BARDA hopes companies can show in smaller trials that they elicit the same type of immune response as currently licensed vaccine doses, which could speed up their availability to the general public.
“The technologies have been demonstrated for other viral pathogens, but we are trying to support them for clinical trials. And again, the timing really depends on being able to identify these correlates for protection, ”Disbrow added.
Un vaccine «pan-coronavirus
Scientists at the Walter Reed Army Research Institute recently announced the first trials of a vaccine based on a “ferritin-tip nanoparticle” that has shown promising results against variants of SARS-CoV-2 as well. than against the earlier virus known as SARS CoV-1.
“For the past four years, we’ve tried to move away from a virus, a vaccine. And we’re really trying to get vaccines for the future, ”says Gordon Joyce, a senior scientist in WRAIR’s Emerging Infectious Diseases branch. .
Unlike other currently licensed vaccines, the experimental doses of WRAIR are designed to deliver modified triplets of spike proteins that they hope will cause the immune system to produce more and more antibody diversity. Similar to other conventional “protein vaccines,” the developers say these doses could prove to be stronger than vaccines that require carefully controlled climates to remain stable.
The researchers say they are in talks with business partners for possible next steps for their shots. The current batch of doses tested could be developed into a “variant-proof” vaccine, booster shots, or simply serve as “proof of principle” for future vaccines for larger groups of coronaviruses.
“We didn’t think we would already be here with a pan-SARS vaccine, but it looks like we might be there,” says Kayvon Modjarrad, director of WRAIR’s Emerging Infectious Diseases branch.