JPA: JPQL count + distinct

Query q = em.createQuery("select "
            + " new com.apalmeira.modelo.followup.Gf( count( distinct p.nome ), u.nome)"
            + " from " + FollowUp.class.getName() + " o"
            + " left join o.pessoa p"
            + " left join o.usuarioResponsavel u"
            + " where"
            + " o.modulo = :modulo and "
            + " o.atividade in (:atividade1, :atividade2, :atividade3) and"
            + " o.mesVigencia between :dataInicio and :dataFim "
            + " group by 2"
            + " order by u.nome");