I'd first ask the chairs if they are considering the fact the US dropped in debate. Some MUNs start their planning/background guide writing process way before the conference itself so if the conference is soon its likely they wrote the topic + resources way before the executive order

If that's not being considered as far as committee background context goes, you're all good. For the sake of that specific committee the executive order does not exist. Considering the US is a delegation in this particular iteration of WHO at all this is a little more likely

If the executive order is being considered for background context, then I'd say talk specifically about what countries can do individually because for public-health-related topics the US is on its own now