The newly identified Omicron variant of Covid has led to more disruption for international travellers.
Quarantine is being reintroduced for people arriving from some African countries, flights have been cancelled and PCR tests will be mandatory within 48 hours of arrival to the UK from 30 November.
Will I be refunded if my holiday is cancelled?
If the government announces that travel to a particular country is not advised, then airlines and travel companies are likely to cancel any pre-booked flights or holidays there.
For example, that is already the case for some flights to and from South Africa as a result of risks associated with the Omicron variant.
If your flight is cancelled, you are entitled to a full refund and you can choose to receive that refund in cash rather than as a voucher.
An airline should refund the money within seven days, although some people have waited longer.
A package holiday should be refunded, in full, within 14 days.
What if I decide it is too risky to travel?
This is far less clear-cut. If you cancel, rather than your travel provider, then you have no automatic right to a refund.
In this situation, it is worth contacting the airline/holiday provider to see what options you have.
EasyJet, for example, has announced that it will extend its "freedom to change" service - which allows passengers to change flights up to two hours before departure for free - until 31 March, 2022.
Some may charge a fee to transfer to another date or destination, but some may allow it without charging a fee. You would have to pay the difference if the alternative flight is more expensive.
They may give you a voucher, or they may allow you to cancel and get a refund.
What about my accommodation costs?
That may be trickier, according to Rory Boland, travel editor at Which? who said that the property's specific policy will determine whether refunds would be given.
"If your trip is several weeks or months away, travellers should at this stage do nothing as the situation may change," he said.
"Those booking a trip should do so through holiday providers with good, flexible booking policies in case it cannot go ahead."
People who have booked a package holiday will be refunded in full, including accommodation, if it is cancelled by the operator.
Can I cancel my holiday if I have to self-isolate?
Operators do not have to refund you if you are unexpectedly forced to self-isolate.
It is best to study their policies before booking, or see whether they can offer some support if you have already booked and want to cancel.
Will travel insurance cover me if I get Covid?
Travel insurers are offering different levels of cover. In part, this depends on how much you pay for a policy.
The majority, but not all, will pay out if you test positive for Covid and have to cancel before you travel.
Importantly, if the Foreign Office advises against travel to a country - as it is for some in southern Africa at the moment, then all but a handful of travel insurance policies would be invalid if you still decide to go.
Why is this so complicated?
Rules are inevitably going to be complex, given the risk of Covid varies so much between countries.
The government has published a charter that "clearly sets out consumer rights and responsibilities when booking travel while Covid-19 measures remain in place".
It says it expects travel operators to be "flexible" with customers, given the circumstances, and the Competition and Markets Authority (CMA) has warned package holiday firms they must stick to refund rules.