One formula worked against multiple species instead of needing a new shot for each one
Em um momento em que o mundo corre atrás de variantes que surgem mais rápido do que as vacinas conseguem acompanhar, pesquisadores das universidades Duke e UNC encontraram uma saída diferente: em vez de perseguir cada nova forma do vírus, identificaram aquilo que todos os coronavírus têm em comum. Publicada na capa da revista Nature em maio de 2021, a vacina 'pancoronavírus' treina o sistema imunológico contra uma assinatura molecular universal presente em toda a família viral — protegendo primatas contra múltiplas espécies do vírus com uma única formulação. É um passo ainda inicial, mas aponta para um futuro em que a ciência deixa de correr atrás da doença e passa a antecipá-la.
- A cada nova variante — brasileira, indiana, sul-africana — fabricantes de vacinas precisam reformular seus produtos, mantendo o mundo preso num ciclo interminável de atualização.
- Pesquisadores identificaram uma região molecular comum a todos os coronavírus, o domínio de ligação ao receptor da proteína spike, abrindo caminho para uma vacina que não precisa ser reescrita a cada mutação.
- Em testes com primatas, a vacina produziu níveis de anticorpos neutralizantes superiores aos das vacinas de mRNA e até maiores do que os observados em animais que sobreviveram à infecção natural.
- Cem por cento dos macacos vacinados foram protegidos contra infecção por diferentes espécies de coronavírus — resultado que o grupo placebo e o grupo com vacina de mRNA não alcançaram.
- A proteção foi menor, mas ainda presente, contra a variante sul-africana, sinalizando que desafios persistem antes de qualquer aplicação humana em larga escala.
- Se confirmada em humanos, a tecnologia poderia encerrar não apenas a corrida contra variantes do SARS-CoV-2, mas também proteger contra futuros saltos zoonóticos de coronavírus ainda desconhecidos.
A pandemia não termina enquanto o mundo não alcançar a imunidade coletiva — mas enquanto países correm para vacinar suas populações, novas variantes continuam surgindo no Brasil, na Índia e em outros lugares, obrigando fabricantes a reformular constantemente seus produtos. É um jogo de perseguição sem fim aparente.
Em maio de 2021, pesquisadores de Duke e da Universidade da Carolina do Norte publicaram na capa da Nature uma abordagem radicalmente diferente. Em vez de mirar uma variante específica, eles mapearam dezenas de tipos de coronavírus e encontraram uma assinatura molecular comum a todos: uma região dentro da proteína spike chamada domínio de ligação ao receptor. Essa região universal se tornou o alvo. A vacina, composta por fragmentos proteicos encapsulados em nanopartículas, treina o sistema imunológico para reconhecer essa característica compartilhada — gerando anticorpos capazes de bloquear múltiplas espécies virais ao mesmo tempo.
Os testes em primatas foram reveladores. Os macacos vacinados produziram níveis de anticorpos muito superiores aos do grupo que recebeu um equivalente das vacinas de mRNA, e até maiores do que os de animais recuperados de infecção natural. Quando expostos a diferentes espécies de coronavírus, 100% dos vacinados foram protegidos. O grupo placebo e o grupo com vacina de mRNA não tiveram a mesma sorte. Contra a variante sul-africana, a proteção foi menor — mas ainda presente.
'O que vimos foi não apenas proteção contra a infecção, mas uma resposta imune cruzada contra as diferentes proteínas spike de vários coronavírus', explicou Barton Haynes, diretor do Instituto de Vacinas Humanas de Duke e líder da pesquisa.
As implicações vão além da COVID-19. Estudos da UNC mostram que coronavírus saltam de animais para humanos repetidamente ao longo da história evolutiva. Uma vacina universal poderia proteger contra variantes ainda por surgir e contra futuros vírus zoonóticos. Testes em primatas não são testes em humanos — mas pela primeira vez, uma vacina eficaz contra toda a família dos coronavírus deixou de ser apenas uma ideia. É um protótipo.
The pandemic will not end until most of the world's population is vaccinated, experts agree. But as countries chase the 60 to 70 percent immunity threshold needed to slow transmission, new variants keep emerging—in Brazil, in India, everywhere. Vaccine makers scramble to update their formulas. Each new strain demands a new shot. It is an exhausting game of catch-up.
Then in May, researchers at Duke University and the University of North Carolina at Chapel Hill published something different. They had engineered a vaccine that works not against one coronavirus variant, but against multiple species of the virus and their mutations. The work appeared on the cover of Nature, one of the world's most prestigious scientific journals.
The key was understanding how the virus enters human cells. All coronaviruses use the same basic tool: a spike protein that acts like a key, fitting into a receptor on the surface of our cells. Within that spike protein sits a smaller region called the receptor binding domain—the RBD. The researchers mapped this region across dozens of different coronavirus types and found something remarkable: a common molecular signature present in all of them. This was the target. They designed their vaccine to train the immune system to recognize this universal feature, generating what scientists call cross-neutralizing antibodies—defenders that could block infection from multiple viral species at once.
The vaccine itself is made of protein fragments bundled into nanoparticles, which ferry the spike protein into the body. Once inside cells, the nanoparticles release their cargo, and the immune system learns to recognize it. An adjuvant—an immune booster—amplifies the response. It is similar in design to vaccines already being made by Novavax.
To test whether it actually worked, the team vaccinated five cynomolgus macaques—a species native to Southeast Asia—with their new vaccine. Others received a placebo or a mimic of the mRNA vaccines already in use against COVID-19. The results were striking. The vaccinated monkeys produced far more IgG antibodies binding to the receptor domain than those given the mRNA mimic. The level of neutralizing antibodies—the kind that actually stop infection—was significantly higher than in the mRNA group and even higher than in animals that had recovered from natural coronavirus infection.
When the researchers tested these antibodies against specific variants, they blocked the British strain and the Brazilian P.1 variant effectively. Against the South African variant, which carries a mutation that weakens antibody response, the protection was lower but still present. Then came the ultimate test: they exposed all the vaccinated monkeys to different coronavirus species. One hundred percent were protected from infection. The placebo group and the mRNA-vaccinated group were not.
Barton Haynes, the lead researcher and head of Duke's Human Vaccine Institute, explained the approach simply: "We basically manufactured multiple small copies of the coronavirus to trigger a strong immune response. What we saw was not just protection against infection, but a cross-reactive immune response against the different spike proteins of various coronaviruses."
The implications reach beyond COVID-19. Other research from UNC has shown that coronaviruses jump from animals to humans repeatedly throughout evolutionary history. A universal vaccine could protect against variants yet to emerge, and against future spillovers from wildlife. It could mean the end of the endless cycle of updates and boosters, the end of chasing variants around the world. It is still early—primate trials are not human trials—but for the first time, a single vaccine that works across the entire coronavirus family is not a dream. It is a prototype.
Notable Quotes
We basically manufactured multiple small copies of the coronavirus to trigger a strong immune response. What we saw was not just protection against infection, but a cross-reactive immune response against the different spike proteins of various coronaviruses.— Barton Haynes, lead researcher, Duke University Human Vaccine Institute
The Hearth Conversation Another angle on the story
Why does the spike protein matter so much? There are other parts of the virus.
The spike protein is how the virus gets inside us. It's the lock and key. If you can teach the immune system to recognize that key across all coronavirus types, you've solved the variant problem at its root.
But the South African variant still got through, even with this vaccine. Doesn't that undermine the whole thing?
It got through less effectively. The protection was lower, yes, but it was still there. No vaccine is perfect against every strain. What matters is that one formula worked against multiple species and most variants, instead of needing a new shot for each one.
The monkeys had 100 percent protection. Will humans?
That's the honest answer: we don't know yet. Primates are a good model, but they're not us. The next step is human trials. But the fact that it worked this well in animals, and better than existing vaccines, is significant.
How long until this is available?
That depends on regulatory approval and manufacturing scale. These things take time. But the science is published, peer-reviewed, and reproducible. Other labs can build on it now.
Does this mean we stop worrying about new variants?
Not immediately. But it means we could stop playing defense forever. Instead of updating vaccines every time a new strain appears, we might have one that covers them all—including variants we haven't even seen yet.