The University of Minnesota is kick-starting a global movement to improve on COVID-19 vaccines, which were developed in the first year of the pandemic and reduced severe illnesses but came with limitations.

"We had concerns about a very good vaccine, saving millions of lives," said Michael Osterholm, director of the U's Center for Infectious Disease Research and Policy, "but not what we actually would have hoped we would have in terms of durability."

Step one was the U's publication of a road map, developed by experts from around the globe, with deadlines for the global scientific community to solve barriers to improved vaccine development and distribution. Step two was Thursday's online forum to reflect on lessons from the current COVID-19 vaccines, which lose effectiveness after a few months and can be vulnerable to viral mutations.

The event followed Monday's federal announcement of a $5 billion initiative to create better vaccines against coronaviruses, including the SARS-CoV-2 virus behind the pandemic.

"We have to stay ahead of the rapidly evolving virus that is SARS-CoV-2," said Dr. Nahid Bhadelia, a senior policy adviser for the White House COVID-19 Response Team.

COVID-19 threats have eased this spring, according to Thursday's weekly state pandemic update. COVID-19 hospitalizations declined in Minnesota on Tuesday to 186, and only included 12 patients needing intensive care — the lowest ICU count since the earliest weeks of the pandemic in 2020. Viral levels in sewage have declined as well statewide, according to a University of Minnesota dashboard, which is a predictor of future pandemic risks.

Minnesota is still reporting about five COVID-19 deaths per day, mostly among seniors, bringing its toll to 14,696. Recipients of initial COVID-19 vaccine booster doses might have lost immunity if those shots were given months ago, prompting federal authorities this week to recommend second boosters for the elderly and people with compromised immune systems.

Interest in boosters is unclear, though, amid declining pandemic indicators. In Minnesota, 94% of seniors have received some COVID-19 vaccine but only 63% are up to date with recommended boosters.

"The rapidly waning immunity leads to the need for frequent boosting, which is logistically difficult and largely unpopular," said Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in New York.

Longer-lasting protection is one goal, but he said future coronavirus vaccines also should be easier to distribute globally and reduce the spread of the virus — rather than just the number of infections that cause severe illness.

Manufacturers have been "laser focused" on vaccines that prompt the body to produce neutralizing antibodies that fight off viruses, but Barouch said a more effective version would also train the body's innate immune system to respond to future infections.

Vaccines that produce antibodies in mucus could help as well, he said, limiting viral growth in the upper respiratory tract in a way that reduces the spread of infection when people cough or sneeze.

More surveillance is needed to identify coronavirus strains that are threatening and capable of passing from bats to animals to humans, said Linfa Wang, director of the Emerging Infectious Diseases Program at Duke-NUS Medical School in Singapore. Results would help in developing vaccines and containing outbreaks early.

Failing that, doctors need to be ready to react to unusual illnesses in people who have had contact with animals so that new viruses can be identified and matched to available vaccines or medications, he said: "If we detect that, we can still respond early."

One of the "biggest failures" in the pandemic response was vaccine access in countries that couldn't afford large quantities, said Charlie Weller, the head of vaccines at Wellcome Trust in England.

Viral spread in those countries allowed the coronavirus to mutate into variants that then evade immunity back in the U.S. and other highly vaccinated countries, she said. Cold storage requirements of the initial COVID-19 vaccines increased the lack of access in poorer countries. Weller said investments are needed in the development of dissolvable "microdermal" patches on skin that would be easier to distribute and administer quickly.