Careful? A hospital employee in Xi’an was infected even after receiving two doses of vaccine

On April 20, the CDC Weekly Report (English) published online an investigation of a hospital examiner in Xi’an who was infected with the new coronavirus despite having received two doses of COVID-19 vaccine. The reason was that she may have been exposed to environmental conditions carrying the UK variant virus 5 days before the onset of the disease.

The case was a mild case and was discharged from the hospital on April 9. The report concluded that vaccination with the new crown vaccine resulted in a patient with mild clinical symptoms, a short disease duration, and a low viral load that was virtually non-infectious. Medical personnel are also reminded that even after vaccination, appropriate personal protection is still required during the treatment of patients with Newcastle pneumonia as prescribed.

On March 17, 2021, this examiner working in the isolation area of the New Crown Designated Hospital was diagnosed with New Crown pneumonia. Her primary job was to collect throat swabs from COVID-19 patients in the isolation ward and perform routine blood, urine and stool testing in the BSL-2 laboratory in the isolation area. Before entering the isolation area to work, she had received two doses of the New Crown vaccine.

Based on epidemiological investigations, it is likely that the examiner was infected on March 12 while collecting throat swabs from 2 cases of Neocrown imported from abroad (returning from Uzbekistan). Virus testing confirmed a high viral load of the British variant (B.1.1.7) of the New Coronavirus in the two foreigners on March 12. On that day, the examiner collected two nasopharyngeal swabs and one oropharyngeal swab from the two patients, a high-risk procedure in which the patients may sneeze or dry heave, thereby excreting high levels of New Coronavirus for a short period of time. Also, this examiner has chronic rhinitis and is used to breathing through his mouth, which can increase the risk of inhaling the virus. Some studies have found that allergic rhinitis and asthma have a greater risk of susceptibility to neocoronavirus infection.

This examiner had a temperature of 37.9°C on the day of diagnosis, a cough and headache, but no dyspnea or shortness of breath, and mild clinical symptoms. on March 19, the maximum temperature was 37.2°C, the cough was slightly worse, and the sense of smell was slightly decreased. on March 20, the temperature was normal, the sense of smell improved, and the symptoms disappeared from the following day. Her oxygen saturation was at a normal level throughout the illness and she was not administered oxygen. on April 9, she recovered and was discharged from the hospital.

Immediately after her onset, 33 colleagues from the same medical team were transferred to another sentinel hospital for isolation and observation. three consecutive qRT-PCR tests performed from March 17 to March 19 were negative, with no fever or other discomfort. Thirty of them were health care workers who completed two doses of vaccination and had positive reactions to the new crown antibodies, with a mean total antibody value of 19.77 (range 1.7 to 150.83) and a mean IgG antibody value of 20.29 (range 3.69 to 64.33), as measured by this assay

Hundreds of environmental samples were collected, including the temporary dormitory of the medical staff in the isolation area, the internal and external environment of the dormitory building and the internal and external environment of other hospital wards. All environmental specimens tested negative for nucleic acid, except for the sample from that examiner’s dormitory, which tested positive.

The report states that 14 days after completing 2 doses of the Neocon vaccine, all 31 health care workers, including the examiner, showed positive serum Neocon antibodies, especially the examiner’s serum antibody titer 2 days after onset was extremely high, indicating effective vaccine immunization. The report also states that no vaccine is 100% effective and that in addition to individual differences and technical reasons for the vaccine transfer and vaccination process, high-risk exposure is an important reason for vaccine protection failure. A phase III clinical trial of the neocrown vaccine also showed that the neocrown vaccine had a lower rate of protection in health care workers treating patients with neocrown pneumonia compared to the general community population. From the clinical course of this examiner, it is highly likely that the patient’s mild symptoms and short duration of illness were due to the neostriatal vaccination.

The report again reminds healthcare workers that clinical management of patients with neocrown pneumonia is a high-risk medical practice that requires proper personal protection and good clinical practice, even after vaccination. Good infection prevention and control measures and proper personal protection are essential to reduce the risk of hospital-acquired COVID-19.