Vaccine breakthrough cases in Washington State to 22nd September 2021
This week’s update from Washington State showing vaccine breakthrough cases and which Sars-CoV-2 variant is causing them up to 22nd September 2021. Vaccine breakthrough cases caused by the Delta variant have increased substantially this week, by just over 500 cases.
As we mentioned in our update last week, the amount of genome sequencing of Sars-CoV-2 samples undertaken by Washington State is decreasing, so the figures below do not represent all vaccine breakthrough cases, just a small percentage.

Vaccine Breakthroughs up to 22nd September 2021
| 22nd Sept 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Delta | B.1.617.2 | 2,951 | 76% | 35% | 501 |
| Alpha | B.1.1.7 | 408 | 11% | 29% | 1 |
| Gamma | P.1 | 206 | 5% | 7% | 4 |
| Epsilon | B.1.429 | 126 | 3% | 10% | 0 |
| Other | Other | 114 | 3% | 14% | 6 |
| Iota | B.1.526 | 35 | 1% | 3% | 0 |
| Epsilon | B.1.427 | 13 | 0% | 1% | 0 |
| Beta | B.1.351 | 11 | 0% | 1% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 3 | 0% | 0% | 0 |
| Total |
Vaccine Breakthroughs up to 15th September 2021
| 15th Sept 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 407 | 12% | 31% | 5 |
| Gamma | P.1 | 202 | 6% | 7% | 3 |
| Epsilon | B.1.429 | 126 | 4% | 11% | 2 |
| Delta | B.1.617.2 | 2450 | 73% | 30% | 190 |
| Iota | B.1.526 | 35 | 1% | 3% | 1 |
| Beta | B.1.351 | 11 | 0% | 1% | 0 |
| Epsilon | B.1.427 | 13 | 0% | 1% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 3 | 0% | 0% | 0 |
| B.1.617.3 | B.1.617.3 | 0 | 0% | 0% | 0 |
| Other | Other | 108 | 3% | 15% | 3 |
| Total | Total | 3359 | 100% | 100% | 204 |
Vaccine Breakthroughs up to 8th September 2021
| 8th Sept 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 402 | 13% | 32% | 3 |
| Gamma | P.1 | 199 | 6% | 7% | 3 |
| Epsilon | B.1.429 | 124 | 4% | 11% | 0 |
| Delta | B.1.617.2 | 2260 | 72% | 29% | 423 |
| Iota | B.1.526 | 34 | 1% | 2% | 0 |
| Beta | B.1.351 | 11 | 0% | 1% | 0 |
| Epsilon | B.1.427 | 13 | 0% | 1% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 3 | 0% | 0% | 0 |
| B.1.617.3 | B.1.617.3 | 0 | 0% | 0% | 0 |
| Other | Other | 105 | 3% | 16% | -7 |
| Total | Total | 3155 | 100% | 100% | 422 |
Vaccine Breakthroughs up to 1st September 2021
| 1st Sept 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 399 | 15% | 33% | 1 |
| Gamma | P.1 | 196 | 7% | 8% | -2 |
| Epsilon | B.1.429 | 124 | 5% | 12% | 0 |
| Delta | B.1.617.2 | 1837 | 67% | 25% | 443 |
| Iota | B.1.526 | 34 | 1% | 2% | 0 |
| Beta | B.1.351 | 11 | 0% | 1% | 0 |
| Epsilon | B.1.427 | 13 | 0% | 1% | 1 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 3 | 0% | 0% | 0 |
| B.1.617.3 | B.1.617.3 | 0 | 0% | 0% | 0 |
| Other | Other | 112 | 4% | 18% | -111 |
| Total | Total | 2733 | 100% | 100% | 332 |
Vaccine Breakthroughs up to 25th August 2021
| 25th August 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Delta | B.1.617.2 | 1394 | 58% | 18% | 546 |
| Alpha | B.1.1.7 | 398 | 17% | 31% | 40 |
| Gamma | P.1 | 198 | 8% | 7% | 12 |
| Epsilon | B.1.429 | 124 | 5% | 11% | 7 |
| Iota | B.1.526 | 34 | 1% | 2% | 6 |
| Epsilon | B.1.427 | 12 | 0% | 1% | 1 |
| Beta | B.1.351 | 11 | 0% | 1% | 1 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 3 | 0% | 0% | 0 |
| Other | Other | 223 | 9% | 27% | -540 |
| Total | Total | 2401 | 100% | 100% | 73 |
Vaccine Breakthroughs up to 18th August 2021
| 18th August 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Delta | B.1.617.2 | 848 | 36% | 12% | 219 |
| Alpha | B.1.1.7 | 358 | 15% | 30% | 6 |
| Gamma | P.1 | 186 | 8% | 7% | 4 |
| Epsilon | B.1.429 | 117 | 5% | 11% | 1 |
| Iota | B.1.526 | 28 | 1% | 2% | 0 |
| Epsilon | B.1.427 | 11 | 0% | 1% | 0 |
| Beta | B.1.351 | 10 | 0% | 1% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 3 | 0% | 0% | 2 |
| Other | Other | 763 | 33% | 35% | 676 |
| Total | Total | 2328 | 100% | 100% | 908 |
Vaccine Breakthroughs up to 11th August 2021
| 11th August 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Delta | B.1.617.2 | 629 | 44% | 12% | 224 |
| Alpha | B.1.1.7 | 352 | 25% | 39% | 9 |
| Gamma | P.1 | 182 | 13% | 9% | 7 |
| Epsilon | B.1.429 | 116 | 8% | 14% | 0 |
| Iota | B.1.526 | 28 | 2% | 3% | 1 |
| Epsilon | B.1.427 | 11 | 1% | 2% | 0 |
| Beta | B.1.351 | 10 | 1% | 1% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 1 | 0% | 0% | 0 |
| Other | Other | 87 | 6% | 20% | 37 |
| Total | Total | 1420 | 100% | 100% | 278 |
Vaccine Breakthroughs up to 4th August 2021
| 4th August 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Delta | B.1.617.2 | 405 | 35% | 10% | 151 |
| Alpha | B.1.1.7 | 343 | 30% | 41% | 6 |
| Gamma | P.1 | 175 | 15% | 9% | 7 |
| Epsilon | B.1.429 | 116 | 10% | 15% | 0 |
| Iota | B.1.526 | 27 | 2% | 3% | 1 |
| Epsilon | B.1.427 | 11 | 1% | 2% | 0 |
| Beta | B.1.351 | 10 | 1% | 1% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 1 | 0% | 0% | 0 |
| Other | Other | 50 | 4% | 19% | -4 |
| Total | 1142 | 100% | 100% | 161 |
Vaccine Breakthroughs up to 28th July 2021
| 28th July 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 337 | 34% | 43% | 29 |
| Gamma | P.1 | 168 | 17% | 10% | 12 |
| Epsilon | B.1.429 | 116 | 12% | 15% | 3 |
| Delta | B.1.617.2 | 254 | 26% | 7% | 141 |
| Iota | B.1.526 | 26 | 3% | 3% | 4 |
| Beta | B.1.351 | 10 | 1% | 1% | 0 |
| Epsilon | B.1.427 | 11 | 1% | 2% | 0 |
| Eta | B.1.525 | 4 | 0% | 0% | 0 |
| Kappa | B.1.617.1 | 1 | 0% | 0% | 0 |
| Zeta | P.2 | 0 | 0% | 0% | 0 |
| Other | Other | 54 | 6% | 18% | 4 |
| Total | 981 | 100% | 100% | 193 |
Vaccine Breakthroughs up to 21st July 2021
| 21st July 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 308 | 39% | 44% | -1 |
| Gamma | P.1 | 156 | 20% | 10% | 9 |
| Epsilon | B.1.429 | 113 | 14% | 16% | 0 |
| Delta | B.1.617.2 | 113 | 14% | 4% | 23 |
| Iota | B.1.526 | 22 | 3% | 3% | 0 |
| Beta | B.1.351 | 10 | 1% | 1% | -1 |
| Epsilon | B.1.427 | 11 | 1% | 2% | 0 |
| Eta | B.1.525 | 4 | 1% | 0% | 0 |
| Kappa | B.1.617.1 | 1 | 0% | 0% | 0 |
| Zeta | P.2 | 0 | 0% | 0% | 0 |
| Other | Other | 50 | 6% | 19% | 0 |
| Total | 788 | 100% | 100% | 30 |
Vaccine Breakthroughs up to 14th July 2021
| 14th July 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 309 | 41% | 44% | 12 |
| Gamma | P.1 | 147 | 19% | 10% | 6 |
| Epsilon | B.1.429 | 113 | 15% | 16% | 0 |
| Delta | B.1.617.2 | 90 | 12% | 4% | 20 |
| Iota | B.1.526 | 22 | 3% | 3% | 1 |
| Beta | B.1.351 | 11 | 1% | 1% | 0 |
| Epsilon | B.1.427 | 11 | 1% | 2% | 0 |
| Eta | B.1.525 | 4 | 1% | 0% | 0 |
| Kappa | B.1.617.1 | 1 | 0% | 0% | 0 |
| Zeta | P.2 | 0 | 0% | 0% | 0 |
| Other | Other | 49 | 6% | 20% | 0 |
| Total | 757 | 100% | 100% | 39 |
Vaccine Breakthroughs up to 7th July 2021
| 7th July 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant | Increase in Number of Breakthroughs From Previous Week |
|---|---|---|---|---|---|
| Alpha | B.1.1.7 | 297 | 41% | 44% | 11 |
| Gamma | P.1 | 139 | 19% | 9% | 6 |
| Epsilon | B.1.429 | 113 | 16% | 16% | 0 |
| Delta | B.1.617.2 | 70 | 10% | 4% | 30 |
| Iota | B.1.526 | 21 | 3% | 3% | 7 |
| Beta | B.1.351 | 11 | 2% | 1% | 1 |
| Epsilon | B.1.427 | 11 | 2% | 2% | 0 |
| Eta | B.1.525 | 4 | 1% | 0% | 0 |
| Kappa | B.1.617.1 | 1 | 0% | 0% | 0 |
| Zeta | P.2 | 0 | 0% | 0% | 0 |
| Other | 49 | 7% | 20% | 0 | |
| Total | 716 | 100% | 100% | 55 |
Vaccine Breakthroughs up to 30th June 2021
| 30th June 2021 Variant | Lineage | Number of Vaccine Breakthrough Cases With Variant | Percentage of Vaccine Breakthrough Cases With Variant | Percentage of Sequences From All Covid-19 Cases With Variant |
|---|---|---|---|---|
| Alpha | B.1.1.7 | 286 | 37% | 38% |
| Gamma | P.1 | 133 | 17% | 8% |
| Epsilon | B.1.429 | 113 | 15% | 14% |
| Delta | B.1.617.2 | 40 | 5% | 2% |
| Iota | B.1.526 | 14 | 2% | 3% |
| Beta | B.1.351 | 10 | 1% | 1% |
| Epsilon | B.1.427 | 11 | 1% | 2% |
| Eta | B.1.525 | 4 | 1% | 0% |
| Kappa | B.1.617.1 | 1 | 0% | 0% |
| Zeta | P.2 | 0 | 0% | 0% |
| Other | 49 | 21% | 32% | |
| Totals | 661 | 100% | 100% |
Image by Cristian Grigore from Pixabay





