The future of COVID-19 vaccine research

We’ve been living in a world with COVID-19 for less than two years, and during that time scientists have learned a tremendous amount. They’ve also developed multiple vaccines that fight the infection. But there is still so much we don’t know about the virus. And we don’t know how long it will take to get those answers.

To learn more about where the research stands and where we need to go next, we spoke with two top California-based scientists. Here’s what they had to say.

Do vaccines prevent transmission?

Research suggests that they do reduce transmission rates. In Israel, more than 50% of the country is fully vaccinated. Cases have plummeted, says Monica Gandhi, MD. She’s the associate division chief of HIV, infectious diseases, and global medicine at the University of California, San Francisco.

“It’s not just hospitalizations. We see lower rates of asymptomatic infection, too,” says Dr. Gandhi. “It makes sense because vaccines usually decrease transmission. It’s just that the initial clinical trials for these vaccines didn’t look at asymptomatic infections.

Multiple studies also suggest that the vaccines can reduce the amount of virus people carry, according to the Centers for Disease Control and Prevention. That helps cut transmission, too.

What’s next: Researchers are now recruiting 12,000 recently vaccinated college students. They’ll swab their noses daily for four months to check infection rates. They’ll also track viral load. They hope to have results by the fall. “If asymptomatic students have very low viral loads, as seen in other studies, that’s good news. [It means] they can’t easily transmit the virus,” says Dr. Gandhi.

How long does immunity last after the shot(s)?

“Right now, we don’t have data yet to know for sure. But it appears [to last] at least six to eight months,” says John Swartzberg, MD. He’s clinical professor emeritus in the division of infectious diseases and vaccinology at the University of California, Berkeley. A recent study published in Science found that around 95% of people who had COVID-19 still had a robust immune response eight months later.

Pfizer released data in April showing its vaccine is 100% effective against severe disease for up to six months. Given that the vaccines have been used widely for only six to eight months, it’s not surprising that we don’t know yet if they’ll last longer. We’ll learn more as each month goes by.

What’s next: The people involved in vaccine clinical trials will still be followed for at least two years, notes Dr. Gandhi. As results become available, we should have a better sense of what efficacy looks like. But even after that, researchers will study the vaccines to decide whether some kind of booster is needed.

How effective are the vaccines against the new variants?

Initial research suggests that you’re still protected, according to the CDC. For instance, the Moderna vaccine appears to be equally effective against the Alpha strain, although less so with Beta. And the World Health Organization has reported that the shots can help prevent severe disease in people infected with the Delta variant.

But even if the vaccines aren’t as effective against the variants, that doesn’t mean they don’t work, adds Dr. Gandhi. “Research shows that your T cells, which are key to your body fighting COVID-19, remain active against the virus even when it’s a variant. That should provide protection, especially against severe disease.”

What’s next: As variants spread, we will continue to get real-life data about how well the current vaccines work against them, says Dr. Gandhi. In the meantime, vaccine makers plan to test booster shots tailored to specific strains.

Are the vaccines safe and effective for pregnant women? Does immunity pass to the fetus?

The answers appear to be yes. “Pregnant women were initially excluded from clinical trials. But it turned out quite a few women got pregnant during the studies. We learned that it did protect them and was safe,” says Dr. Swartzberg. The CDC has since launched a COVID-19 pregnancy registry. So far more than 130,000 pregnant women have gotten the vaccine without any unusual side effects.

Other good news: A small study recently found COVID-19 antibodies in new moms’ umbilical cord blood and breast milk. That suggests that immunity was passed on to their babies.

What’s next: Pfizer launched a study of more than 4,000 healthy pregnant women this past February. They and their infants will be followed for 7 to 10 months. The goal is to see if the babies develop protective antibodies against the virus. The CDC will also continue to monitor women through its pregnancy registry, adds Dr. Gandhi.

Are the vaccines safe and effective in younger children and babies?

We don’t know yet. Pfizer announced the results of its clinical trials in kids ages 12 to 15 this past March. The vaccine was safe and 100% effective in this age group. The FDA authorized the shot for use in May for kids 12 and up. But studies still need to be conducted in younger children. “First, they have to figure out the best dose to give them. Generally, it’s a quarter or a half of what’s given to adults,” explains Dr. Gandhi. “Then they have to test the vaccine for safety and ability to generate an immune response.”

What’s next: Both Pfizer and Moderna began to study their COVID-19 vaccines in children under the age of 12 in March. In April, Johnson & Johnson began testing its shot in kids ages 12 to 17. But the results of all these studies may not be available until this fall, notes Dr. Gandhi. That means that most younger kids likely won’t be able to get vaccinated until late 2021 or early 2022.

Are there any long-term side effects of the vaccine?

Probably not. “If you look at the vaccines we have developed over the last 115 years, you’ll see that almost all of the serious side effects occur in the first six weeks,” says Dr. Swartzberg. “We haven’t seen [many long-term ones].”

Very rarely, the shot from Johnson & Johnson may be associated with blood clots and low platelets within the first few weeks. The condition occurs in about 7 of every 1 million vaccinated women under age 50, according to the CDC. Because of this, experts are recommending that you watch for the following symptoms for three weeks after receiving this shot: 

• Severe or persistent headaches or blurred vision
• Shortness of breath
• Chest pain
• Leg swelling
• Persistent abdominal pain
• Easy bruising or tiny blood spots under the skin beyond the injection site

Although it’s unlikely that you’ll experience these signs, it’s important to seek medical care quickly if you do. 

There have also been some reports of heart inflammation after receiving the Pfizer and Moderna vaccines. It mostly affected young men and boys 16 and older, according to the CDC. The condition tended to begin within a few days, and most patients recovered quickly with treatment. Symptoms to watch for include chest pain, shortness of breath and palpitations.

There is some good news: The vaccines do appear to help ease some of the symptoms of COVID-19 that can occur among “long haulers,” people whose symptoms can linger for weeks or even months, says Dr. Gandhi. “We don’t know why that is, but it seems as if it actually tames down the out-of-whack immune response that can occur among some people infected with COVID-19.”

What’s next: Vaccine manufacturers will continue to follow trial participants to watch for long-term effects. The CDC will continue to monitor vaccine safety with its vaccine registry.

All Californians ages 5 and older are eligible for the COVID-19 vaccine. To learn how to schedule your appointment, visit My Turn.

The information in this story is accurate as of press time and posting. To limit the spread of the coronavirus, it’s important to continue practicing social distancing (keeping at least 6 feet away from people outside your household) and washing your hands frequently. You should also be appropriately masked per CDC guidelines. Because the situation surrounding COVID-19 continues to evolve, we encourage readers to follow the news and recommendations for their own communities by using the resources from the CDC, WHO, their local public health department, and our COVID-19 member site.

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