Epidemic Situation

Year: Week:

NATIONAL WEEKLY INFLUENZA BULLETIN OF THE RUSSIAN FEDERATION

week 2 of 2022 (10.01.22 - 16.01.22)

Summary

Influenza and ARI incidence data. Influenza and other ARI activity increased in Russia in comparison with previous week. The nationwide ILI and ARI morbidity level (72.6 per 10 000 of population) was higher than national baseline (70.0) by 3.7%.

Etiology of ILI & ARI. Among 5313 investigated patients 742 (14.0%) respiratory samples positive for influenza detected in 43 cities, including 655 cases of influenza A(H3N2) in 41 cities, 69 cases of influenza A unsubtyped in 7 cities and 18 cases of influenza B in 5 cities.

ARVI detections. The overall proportion of respiratory samples tested positive for other ARVI (PIV, ADV, RSV, RhV, CoV, MPV, BoV) was estimated in total as 7.9% (PCR).

In sentinel surveillance system clinical samples from 74 SARI patients were investigated by rRT-PCR, among them 15 (20.3%) cases of influenza A(H3N2) recognized. Among clinical samples from 59 ILI/ARI patients 6 (10.2%) cases of influenza A(H3N2) detected. Among 67 SARI patients 7 (11.1%) cases positive for ARVI recognized including one case of ADV, 2 cases of RSV, one case of RhV, 2 cases of CoV and one case of BoV infection. Among 43 ILI/ARI patients 6 (14.0%) cases were positive for ARVI, including one case of PIV, 3 cases of RSV, one case of RhV and one case of MPV infection. 3 (4.3%) of 69 SARI patients were positive for coronavirus SARS-CoV-2. Among 58 ILI/ARI patients no cases positive for coronavirus SARS-CoV-2 recognized.

Antigenic characterization. Since the beginning of the season, 143 influenza A(H3N2) viruses have been antigenically characterized by the NICs (Moscow and Saint-Petersburg). 96 viruses were antigenically closely related to vaccine strain A/Cambodia/e0826360/20 (H3N2), however 36 strains were poorly recognized (1/16-1/32 of the homological titer) by rat antiserum to vaccine strain. 11 viruses were antigenically similar to reference strain A/Darwin/9/2021 (H3N2).

Susceptibility to antivirals. All 122 influenza A(H3N2) viruses analysed by the NICs (Moscow and Saint-Petersburg) were susceptible to oseltamivir and zanamivir.

COVID-19. Totally 10 938 261 cases and 324 060 deaths associated with COVID-19 were registered in Russia including 38 850 cases and 684 deaths in last 24 hours (on 12:00 of 20.01.2022). According to the data obtained by NIC in Saint-Petersburg totally 17414 clinical samples were PCR investigated in last week. Among them coronavirus SARS-CoV-2 detected in 5484 (31.5%) cases.

Influenza and ARI morbidity data

Fig. 1. Influenza and ARVI morbidity in 61 cities under surveillance in Russia, seasons 2020/21 and 2021/22
Rates per 10 000 populationFig. 1. Influenza and ARVI morbidity in 61 cities under surveillance in Russia, seasons 2020/21 and 2021/22

Weeks

  • Morbidity 2021/22Morbidity 2021/22
  • Morbidity 2020/21Morbidity 2020/21
  • MEM baseline 2021/22MEM baseline 2021/22

Epidemiological data showed inrease of influenza and other ARI activity in Russia in comparison with previous week. The nationwide ILI and ARI morbidity level (72.6 per 10 000 of population) was higher than national baseline (70.0) by 3.7%.

Fig. 2. Comparative data on incidence rate of clinically diagnosed influenza, seasons 2020/21 and 2021/22
Rates per 10 000 populationFig. 2. Comparative data on incidence rate of clinically diagnosed influenza, seasons 2020/21 and 2021/22

Weeks

  • Season 2021/22Season 2021/22
  • Season 2020/21Season 2020/21
  • MEM baselineMEM baseline

Incidence rate of clinically diagnosed influenza increased comparing to previous week and amounted to 0.19 per 10 000 of population, it was 3.2 times higher than pre-epidemic MEM baseline (0.060).

Fig. 3. Comparison of hospitalization rate with clinical diagnosis of influenza, seasons 2020/21 and 2021/22
Rates per 10 000 populationFig. 3. Comparison of hospitalization rate with clinical diagnosis of influenza, seasons 2020/21 and 2021/22

Weeks

  • Season 2021/22Season 2021/22
  • Season 2020/21Season 2020/21
  • MEM baselineMEM baseline

Hospitalization rate of clinically diagnosed influenza decreased comparing to previous week and amounted to 0.087 per 10 000 of population, it was 2.2 times higher than pre-epidemic MEM baseline (0.040).

Influenza and ARVI laboratory testing results

Cumulative results of influenza laboratory diagnosis by rRT-PCR were submitted by 46 RBLs and two WHO NICs. According to these data as a result of 5313 patients investigation 742 (14.0%) respiratory samples positive for influenza were detected in 43 cities, including 655 cases of influenza A(H3N2) in 41 cities, 69 cases of influenza A unsubtyped in 7 cities and 18 cases of influenza B in 5 cities.

Antigenic characterization. Since the beginning of the season, 143 influenza A(H3N2) viruses have been antigenically characterized by the NICs (Moscow and Saint-Petersburg). 96 viruses were antigenically closely related to vaccine strain A/Cambodia/e0826360/20 (H3N2), however 36 strains were poorly recognized (1/16-1/32 of the homological titer) by rat antiserum to vaccine strain. 11 viruses were antigenically similar to reference strain A/Darwin/9/2021 (H3N2).

Susceptibility to antivirals. All 122 influenza A(H3N2) viruses analysed by the two NIC (Moscow, Saint-Petersburg) were susceptible to oseltamivir and zanamivir.

Fig. 4. Geographic distribution of RT-PCR detected influenza viruses in cities under surveillance in Russia, week 2 of 2022
Fig. 4. Geographic distribution of RT-PCR detected influenza viruses in cities under surveillance in Russia, week 2 of 2022
PCR results
  • No dataNo data
  • No viruses detectedNo viruses detected
  • H1pdm09H1pdm09
  • H3H3
  • H3+H1pdm09H3+H1pdm09
  • BB
  • B+H1pdm09B+H1pdm09
  • B+H3B+H3
  • B+H3+H1pdm09B+H3+H1pdm09
  • A (not subt.)A (not subt.)
  • A (not subt.)+H1pdm09A (not subt.)+H1pdm09
  • A (not subt.)+H3A (not subt.)+H3
  • A (not subt.)+H3+H1pdm09A (not subt.)+H3+H1pdm09
  • A (not subt.)+BA (not subt.)+B
  • A (not subt.)+B+H1pdm09A (not subt.)+B+H1pdm09
  • A (not subt.)+B+H3A (not subt.)+B+H3
  • A (not subt.)+B+H3+H1pdm09A (not subt.)+B+H3+H1pdm09
Fig. 5. Monitoring of influenza viruses detection by RT-PCR in Russia, season 2021/22
Number of positive casesFig. 5. Monitoring of influenza viruses detection by RT-PCR in Russia, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • A (not subt.)A (not subt.)
  • % positive% positive
Fig. 6. Monitoring of ARVI detection by RT-PCR in Russia, season 2021/22
Number of positive casesFig. 6. Monitoring of ARVI detection by RT-PCR in Russia, season 2021/22

Weeks

  • PIVPIV
  • ADVADV
  • RSVRSV
  • RhVRhV
  • CoVCoV
  • MPVMPV
  • BoVBoV

ARVI detections. The overall proportion of respiratory samples tested positive for other ARVI (PIV, ADV, RSV, RhV, CoV, MPV, BoV) estimated as 7.9% of investigated samples by PCR.

Fig. 7. Monitoring of influenza viruses isolation in Russia, season 2021/22
Number of positive casesFig. 7. Monitoring of influenza viruses isolation in Russia, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • % positive% positive

Table 1. Results of influenza and other ARVI detection by RT-PCR in Russia, week 2 of 2022

  Number of  specimens / number of positive cases  % positive
Influenza
Number of specimens tested for influenza 5313 -
Influenza A (not subt.) 69 1,3%
Influenza A(H1)pdm09 0 0,0% 
Influenza A(H3) 655 12,3% 
Influenza B 18 0,3% 
All influenza 742 14,0%
Other ARVI
Number of specimens tested for ARVI 5005  -
PIV 22 0,4%
ADV 58 1,2%
RSV 148 3,0%
RhV 100 2,0%
CoV 34 0,7%
MPV 14 0,3%
BoV 20 0,4%
All ARVI 396 7,9%
SARS-CoV-2 (COVID-19)
Number of specimens tested for SARS-CoV-2 17414 -
SARS-CoV-2 5484 31,5%
Fig. 8. Results of PCR detections of SARS-CoV-2 in Russia
Fig. 8. Results of PCR detections of SARS-CoV-2 in Russia
% positive
  • No dataNo data
  • less then 10%less then 10%
  • 10-20%10-20%
  • 20-30%20-30%
  • 30-40%30-40%
  • 40-50%40-50%
  • 50% and more50% and more

COVID-19. Totally 10 938 261 cases and 324 060 deaths associated with COVID-19 were registered in Russia including 38 850 cases and 684 deaths in last 24 hours (on 12:00 of 20.01.2022). According to the data obtained by NIC in Saint-Petersburg totally 17414 clinical samples were PCR investigated in last week. Among them coronavirus SARS-CoV-2 detected in 5484 (31.5%) cases.

Table 2. Results of influenza viruses isolation in Russia, week 2 of 2022

  Number of specimens / number of viruses  % isolated viruses
Number of specimens 28 -
Influenza A(H1)pdm09 0 0,0% 
Influenza A(H3) 12 42,9% 
Influenza B 0 0,0% 
All influenza 12 42,9%

Sentinel influenza surveillance

Clinical samples from 74 SARI patients were investigated by rRT-PCR for influenza, among them 15 (20.3%) cases of influenza A(H3N2) recognized. 63 SARI patients were investigated for ARVI by rRT-PCR, among them 7 (11.1%) cases of ARVI recognized including one case of ADV, 2 cases of RSV, one case of RhV, 2 cases of CoV and one case of BoV infection. 3 (4.3%) of 69 SARI patients were positive for coronavirus SARS-CoV-2.

Clinical samples from 59 ILI/ARI patients were investigated for influenza and ARVI by rRT-PCR, among them 6 (10.2%) cases of influenza A(H3N2) recognized. 6 (14.0%) of 43 ILI/ARI cases were positive for ARVI including one case of PIV, 3 cases of RSV, one case of RhV and one case of MPV infection. None of 58 ILI/ARI patients were positive for SARS-CoV2.

Fig. 9. Monitoring of influenza viruses detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22
Number of positive casesFig. 9.  Monitoring of influenza viruses detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • A (not subt.)A (not subt.)
  • % positive% positive
Fig. 10. Monitoring of influenza viruses detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22
Number of positive casesFig. 10.  Monitoring of influenza viruses detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22% positive

Weeks

  • H1pdm09H1pdm09
  • H3H3
  • BB
  • A (not subt.)A (not subt.)
  • % positive% positive
Fig. 11. Monitoring of ARVI detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22
Number of positive casesFig. 11.  Monitoring of ARVI detection by RT-PCR among SARI patients in sentinel hospitals, season 2021/22

Weeks

  • PIVPIV
  • ADVADV
  • RSVRSV
  • RhVRhV
  • CoVCoV
  • MPVMPV
  • BoVBoV
Fig. 12. Monitoring of ARVI detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22
Number of positive casesFig. 12.  Monitoring of ARVI detection by RT-PCR among ILI/ARI patients in sentinel polyclinics, season 2021/22

Weeks

  • PIVPIV
  • ADVADV
  • RSVRSV
  • RhVRhV
  • CoVCoV
  • MPVMPV
  • BoVBoV
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