https://www.mercurynews.com/2021/10/15/jj-vaccine-two-doses-needed-says-f-d-a-panel/

The Johnson & Johnson vaccine works best as a two-dose regimen — and a second shot should now be offered to anyone who got their first dose more than two months ago, according to a Friday vote by a U.S. Food and Drug Administration panel.

But new results from a federal trial show that a potentially better strategy is on the horizon: switching vaccines to boost immunity, where J&J recipients are offered access to either the Pfizer or Moderna vaccine.