SSI: BA.5 Now Dominant COVID In Denmark

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Due to their relatively small population (5.8 million) and a well-monitored universal healthcare system, Denmark's ability to track and report on COVID is among the best in the world.

And with Denmark seemingly just a couple of weeks ahead of the United States when it comes to the spread of the BA.5 variant, what they are seeing there today may give us a good idea of what to expect here a few weeks from now.

A week ago Denmark reported that BA.5 made up roughly 29% of all COVID cases in that country (see Denmark SSI: Increased Cases & Hospitalizations With Rise of Omicron BA.5), and warned that while cases appeared no more severe than with BA.1/BA.2, hospitalizations had increased by 23% over the previous week. 

Seven days later Denmark's SSI is reporting that BA.5 has become the dominant strain and now accounts for 59.3% of all cases. They also reported another 42% increase in hospitalizations, although ICU admissions remain reassuringly low.  

Although Denmark's Weekly Trend Report is primarily written in Danish, I've translated this week's summary from the SSI below.

BA.5 is now the dominant variant


Covid-19 infection is rising markedly, and the sub-variant BA.5 is, as expected, now the variant that accounts for the largest share of new cases of infection. This is shown by the latest trend report from the Statens Serum Institut.

Last edited June 23, 2022

The Covid-19 epidemic is once again on the rise in Denmark. From week 23 to week 24 alone, the number of new cases of infection has grown from 5,830 cases to 8,258 cases. This corresponds to an increase of almost 42% in just one week.

At the same time, there is an increase in the SARS-CoV-2 concentration in wastewater at the national level, so that it is now up to the same level as at the end of April. The increase is seen in all five regions.

This is shown by the latest trend report from the Statens Serum Institut (SSI).

Here you can see the new trend report

BA.5 has become dominant

As previously assessed, the covid-19 sub-variant BA.5 is now the dominant variant.

Back in early May, BA.5 accounted for only a very small proportion of the new cases of infection. In week 23 this proportion had grown to 46.8% of cases, and in week 24 BA.5 so far amounts to 59.3%.

At the same time, the sub-variants BA.4 and BA.2.12.1 now account for 8.4% and 10%, respectively.

Increasing incidence and test activity

The increasing infection rates can also be seen in the incidence, which has increased from 99 cases per. 100,000 inhabitants in week 23 to 140 cases per. 100,000 inhabitants the following week.

At the same time, the number of PCR tests has increased from 37,349 tests performed in week 23 to 45,620 tests performed in week 24. This corresponds to a growth of just over 22%.

Finally, the positive percentage increased between week 23 and week 24 from 16.9% to 19.4%. Thus, almost every fifth test performed is positive.

More inpatients, but fewer in intensive care

The number of covid-19-related admissions is also on the rise. From 220 new inmates in week 23 to 315 new inmates in week 24.

The number of covid-19-related inpatients on the intensive care unit, on the other hand, is going the opposite way, and in the same period has fallen from 9 to 4 inpatients.

"This pattern, both in Denmark and internationally, continues to support that there are currently no signs that BA.5, despite increased infectivity, seems to give more serious disease courses," says ward doctor Rebecca Legarth from SSI.

(Continue . . . )

From this week's 36-page Trends Report, we get this overall assessment (in English).

Overall assessment 

The number of new COVID-19 cases continues increasing between week 23 and 24 with a growth of 42%, and the incidence on a national level has risen to 140 cases per 100.000 inhabitants. The test activity has increased in week 24 and there has been an average of 6,500 daily PCR tests. The rise in the number of new cases happens as the positive percentage increases both nationally, across all regions and in most age groups. 

The number of hospitalizations has increased by 43% in week 24 and the proportion admitted because of COVID-19 has increased in week 22 (the latest week it is possible to create these data for). Patients in age groups 50-89 years constitute the largest groups among the hospitalized. The increase in both number of new cases and in positive percentage among personnel in the health care- and social sector continues to increase in week 24. 

Overall, we see an increasing incidence, rising positive percentages across age groups and geography as well as increasing concentrations of SARS-CoV-2 in wastewater samplings and it is estimated that there is an increasing wide dispersion of infections driven by the emergence of BA.5. BA.5 accounts provisionally for 59% of the sequenced tests in week 24 and is thus assessed to be the dominant variant in Denmark.

On this background there is a continued high likelihood of rising SARS-CoV-2 case numbers along with the growth of BA.5. However, the magnitude of a new infection wave with BA.5 remains uncertain at this point in time as several factors must be expected to influence the development, such as the expected seasonal effect and decreased activity in society during the summer. The increase in hospital admissions seen in week 23 continues in week 24 and especially seen among the older age groups. 

There are until now no signs that BA.5 should lead to an increased risk of severe course of infection, however, it is still appraised that there is a high risk that rising infections rates could lead to corresponding hospital admissions in the coming weeks.

Everything we're seeing suggests that BA.5 (and BA.4) are more likely to evade prior immunity than earlier variants, meaning that even those who have (even recently) recovered from the virus - or have received their booster vaccination - may be at risk of infection. 

Although prior immunity likely decreases your odds of serious illness, yesterday I spoke to an acquaintance - fresh out of 2 weeks in the hospital - following her 4th bout with COVID. 

A reminder that generally mild doesn't mean mild for everyone.  And given what we know about `Long COVID', and emerging evidence on the deleterious impact on the offspring from maternal COVID infection,  even a `mild' COVID virus deserves our respect. 

While I'm glad I got my 2nd booster shot earlier this month, I'm relying more on face masks, hand sanitizer, and avoiding crowds whenever possible, to protect against BA.5.  

And even with those added  precautions, I expect I'll need a bit of luck to avoid infection.