By LAURAN NEERGAARD AP Medical Writer
Two COVID-19 vaccines might be nearing the finish line, but scientists say it’s critical that enough people volunteer to help finish studying other candidates. Moderna and competitor Pfizer recently announced preliminary results showing their vaccines appear to be strongly effective. More vaccine types will be needed to meet global demand. And different types may work better in different people, something only testing can tell. Most vaccines in late-stage testing around the world target the “spike” protein on the coronavirus surface but they’re made using a variety of technologies, some of them brand new. Still, some countries are sticking with older vaccine approaches.