Whether pre-symptomatic or asymptomatic, people not showing symptoms can spread the virus, which is why wearing masks and keeping distance are important to limiting transmission.
Companies and organizations that provide diagnostics serve an important role and must overcome many challenges inherent to developing diagnostic solutions. These areas include research and development, the regulatory environment, production and manufacturing, commercialization, and insurance and reimbursement.
When pathogens get past those preliminary defenses, your body mounts an immune response. Your innate immune system responds first and employs several types of cells and molecules to fight off pathogens, each with their own jobs.