The mRNA-based Covid vaccines helped blunt the impact of the pandemic but also sparked political backlash that has threatened to slow or derail dozens of potential cancer treatments. Now there are signs that the mRNA train is still on track. Editor's note: This story was reported in collaboration with the Global Health Reporting Center with support from the Pulitzer Center. (CNN) — Vita Sara Blechner’s life changed on a Saturday afternoon. The middle school librarian was home in Oceansid... [17020 chars]