They examined the viral load in various clinical samples from ventilated COVID-19 patients. What does the viral load reveal about the clinical prognosis of patients? For which group of people does this apply?
Henrike Maass: Unfortunately, a clear clinical prognosis is not possible based on the viral load alone. Especially in serum samples, the viral load can only be detected in particularly seriously ill patients, since the virus first multiplies in the upper and lower respiratory tract. Nevertheless, our data show that the viral load can be used, among other things, to identify which patients are likely to have a serious course and therefore need additional treatment.
Luka Cicin-Sain: We found this connection in seriously ill patients, where taking samples from the lungs did not cause any additional stress for the patients. Due to ethical considerations and patient care, we could not obtain such samples from the lungs of people with a milder course and then also not analyze them. The viral load in the blood serum of these patients can still be measured. The rule of thumb is: The patients with a very severe course showed a detectable virus titer in the bloodstream.
What kind of samples did you examine in the study? Are there any special considerations?
HM: In the study, we examined serum samples on the one hand and samples from the bronchoalveolar lavage (BAL) on the other. The special thing about BAL samples is that they come directly from the lungs. The lungs are flushed with saline solution, and then the fluid is suctioned out. Since the procedure for this is much more complicated and time-consuming than for serum samples, this type of sample is not used very often. Fortunately for us, these samples are used in Croatia as a diagnostic tool to identify infections with bacterial lung pathogens, which enabled us to use these samples for our study. Another point is that since BAL fluids come straight from the lungs — the area where the virus multiplies — they are highly infectious, unlike blood. To analyze this material, we worked in the S3** laboratory at the HZI. This laboratory meets the high safety standards to work with such infectious samples.
The clinical samples were taken in the second and third corona waves in Croatia. Which virus variants were predominant at the time and were there differences between the variants?
HM: During the second wave period there were mainly variants called pre-alpha. At the time of the third wave, virus variant alpha was dominant. In most of our analyzes we combined the two cohorts. However, in a separate analysis, we found that alpha-infected patients had higher viral loads, both in serum and in BAL samples. In the near future we will do more research with Delta-infected patient samples and see how this variant compares to the previous ones. First preliminary results of these patients also show that the viral load in patients who died from the infection is higher than that of the survivors.
How could these study results improve the treatment of COVID-19?
LCS: Firstly, in this study we showed for the first time that the viral load in the lungs has a significant correlation with the severity of the disease. This is important because previous studies have not found any correlation, but viral load has always been measured in the upper airways because it is easier to do. However, the viral load in the lungs is more important for the course of the disease and our results have also confirmed this. Thus, our data again suggest that treatment with antiviral drugs after admission and before admission to the intensive care unit makes sense to reduce the viral load in the lungs. On the other hand, our study provides further evidence that the patients die because of their SARS-CoV-2 infection and not “with Corona”. Results from animal experiments have already shown that a higher viral load in the lungs also causes higher mortality. Our data show that this association also occurs in humans.
Originalpublikation:
Ynga-Durand M *, Maaß H *, Milošević M, Krstanović F, Pribanić Matešić M, Jonjić S, Protić A, Brizić I, Šustić A, Čičin-Šain L. SARS-CoV-2 Viral Load in the Pulmonary Compartment of Critically Ill COVID-19 Patients Correlates with Viral Serum Load and Fatal Outcomes. Viruses. 2022; 14 (6): 1292. DOI: 10.3390 / v14061292
You can also find this expert interview on our homepage under the link https://www.helmholtz-hzi.de/de/aktuelles/news/news-detail/article/complete/covid-19-viruslast-in-lunge-unterstuetzt-prognose -for-seriously-ill-patients/
