Pre-Christmas Covid tests – what type to get in France

A medical professional performs a nasal swab on a patient
Photo: Valery Hache / AFP
Christmas is coming - and the French government has advised that anyone holding or attending a get-together over the festive period should first have a Covid test. So what is the best type to take?

“Laboratories, doctors, pharmacies test the equivalent of 10 percent of the French population every week,” Health Minister Olivier Véran told the French parliament last week.

And that’s set to rise, with the government advising people who intend to travel or attend a get-together over the Christmas and New Year period to take a test beforehand, especially if you intend to see vulnerable people such as the elderly or ill.

EXPLAINED Health rules and official advice for Christmas and New Year in France 

But it is not always easy to know which test to choose according to your situation, especially since not all methods give the same results. Here are the options:

Nasopharyngeal PCR tests

What are they? 

PCR tests – named after the way in which they are analysed – were the first available in France are the most well-known. This analysis can only be done in a laboratory and it takes several hours to get a result, while the test itself must be carried out by a professional. 

Nasopharyngeal PCR tests are the most common and involve taking a mucus sample with a swab that is inserted into the nasopharynx, a cavity behind the nostril – which can feel a little uncomfortable at the time.

(article continues below)

See also on The Local:

How accurate are they? 

The probability of false negatives or false positives is “almost nil,” according to Vincent Enouf, deputy head of the National Reference Centre for Respiratory Infections Viruses, which was responsible at the beginning of the pandemic for assessing the reliability of the tests. 

“Today, in RT-PCR, we have very sensitive methods [of testing and analysing],” he told France Info.

Will they detect the Omicron variant?

While it’s true that new variants can affect the reliability of all tests, all the evidence so far is that these PCR tests pick up the Omicron variant.

When should you use a PCR test?

The Haute Autorité de Santé (HAS) recommends using PCR tests whenever possible. It is especially recommended for anyone who displays Covid-19 symptoms, and it is recommended that anyone who has a positive result from another test takes a confirmatory Nasopharyngeal PCR.

What’s the downside?

The downside is the time it takes to confirm results. The delay is routinely several hours, and may be a day or so, if labs are busy. Also, they are more expensive than other tests for anyone taking them without a legitimate health reason, and they’re not as widely available as antigen tests.

How to get one

PCR tests are available at medical testing laboratories, in selected pharmacies and in some, but not all, pop-up testing centres. They usually need to be booked in advance, which can be done by phone at your nearest testing centre, online or via medical apps like Doctolib. They are free to fully vaccinated people or those with symptoms or contact cases. Unvaccinated people who do not have symptoms, or people who are not resident in France are charged up to €44 for a PCR test.

Nasopharyngeal antigen tests

What are they? 

Nasopharyngeal antigen tests detect particular proteins produced by the virus in the body. The most common tests use the same swab-up-the-nose method as PCR methods.

How accurate are they?

Officially, antigen tests sold in France must be able to demonstrate accuracy levels between 80 percent and 99 percent. This equates to a one-in-five risk of a false negative, and a one-in-100 risk of a false positive. They must also not confuse the Sars-CoV-2 virus with another.

In reality, the window of detection is smaller with an antigen test than with a PCR. An HAS study in November found that results varied depending on whether those tested were asymptomatic.

Will they detect the Omicron variant?

As with PCR tests, variants of Covid could affect the accuracy of the tests, if they have mutations in the protein that it looks for. In the case of the Omicron variant, antigen tests look for a different protein to the mutated spike protein, so they will detect it, according to a study at the end of November.

When should they be used? 

Antigen tests may be used as a preliminary test by anyone who has been symptomatic for less than five days. It is also the type of test recommended if you are a contact case and have no symptoms and as a pre-holiday test.  

Results come through quickly – within a matter of minutes – but any positive result must be confirmed by a PCR test.

What are the downsides?

They’re quicker, cheaper and easier to get than PCR tests – pharmacies offer them – but accuracy levels are lower. And, if you test positive, you still have to take a PCR to confirm.

How to get one

Antigen tests are available from almost all pharmacies and testing centres and pharmacies mostly operate on a walk-in basis, although you can also book in advance by phone or online. In some cases the results are handed over on the spot, in others they are sent by SMS or email, but in all cases you should have the result within 30 minutes.

They are free to fully vaccinated people or those with symptoms or contact cases. Unvaccinated people who do not have symptoms, or people who are not resident in France are charged up to €22 for an antigen test.

Home tests

What are they?

These are basically antigen tests that you can buy at a pharmacy and do at home, by yourself, sticking the swab up your own nose – they work by looking for the same protein. But the size of the swab means you cannot push it as far up your own nose, making it a nasal rather than a nasopharyngeal test.

How accurate are they?

Similar to the nasopharyngeal antigen tests carried out by pharmacies, minimum standards apply, but much depends on the person self-administering the test.

An HAS study back in August decided that home antigen tests may be considered to be as accurate as pharmacy-performed ones only if carried out ‘under the supervision of a health professional’.

The government is, unsurprisingly, cautious about the value of results from self-tests – but points out that repeated testing increases levels of accuracy.

Will they detect the Omicron variant?

Yes. With the ever-present ‘if used correctly’ warning.

When should they be used? 

The HAS only recommends these tests be used by asymptomatic people who have no reason to believe they are contact cases, for self-reassurance before any family gatherings over the festive period.

Even after taking a home test, the advice is to respect strict barrier measures.

They are also used in mass screening campaigns, notably in the French education system, where they have been distributed to all students in their first year at collège (those aged 11 and 12).

What are the downsides?

Because they’re not routinely administered by health professionals, home tests results are not considered accurate – though multiple tests over a period of days will improve this. They also cannot be used for travel purposes or for the health pass. Positive results have to be confirmed by a PCR test.

How to get one

Boxes of autotests (self-tests) are available in most pharmacies for €5. They are not reimbursed on the carte vitale.

These three are the main test methods used in France, but there are two other options that are only used for certain groups.

Oropharyngeal tests

What are they?

These are tests where the sample is taken from the back of the throat, rather than the nose. Both PCR and antigen oropharyngeal tests are available.

How accurate are they?

The HAS said in September that mouth swab tests results were ‘acceptable’, but did not provide any data. A month earlier, the Haut Conseil de Santé Publique said these PCR tests using this method provided the same results as nasopharyngeal testing in 76 percent of cases, rising to 85.2 percent for positive results.

Will they detect the Omicron variant?

Yes. They are PCR or antigen tests. The method of sampling is different, that is all.

When should they be used?

The HAS recommends these tests only in the context of mass screening or testing of asymptomatic contacts when a swab up the nose is more difficult, such as “young children, very elderly patients, patients with psychiatric disorders, people with a nasal deviation…”

What are the downsides?

The analysis process is more difficult than from nasopharyngeal tests, experts say, and the sampling method means sticking a swab down the patient’s throat, which could produce a gag reflex.

Saliva tests

What are they?

It’s a spit test. You spit into a clean pot, and the contents are taken away for analysis. 

How accurate are they?

A salivary PCR test is not as accurate as the mouth or nose swab ones – but the risk of a false negative remains less than five percent of subjects tested, according to France’s HAS.

Will they detect the Omicron variant?

Yes. 

When should they be used?

Saliva PCR tests are recommended for contact screening or mass testing campaigns for people for whom nasopharyngeal testing is difficult. They are primarily used to test younger children.

What are the downsides?

Accuracy, and – as with mouth-swab tests – additional obstacles to getting results because of the nature of the sample.

Isn’t there another type of spit test?

“Isothermal amplification” tests (also called RT-Lamp), a technique that produced results in less than an hour, were delisted as formal tests in France in July, over concerns about accuracy, especially as antigen, or lateral flow tests, produced more accurate results more rapidly. 


Member comments

Become a Member to leave a comment.Or login here.