November 30, 2023

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Co-infection with COVID-19 and Flu

Co-infection with COVID-19 and Flu

Co-infection with COVID-19 and Flu.  Chinese Top Expert: Zhong Nanshan: There have been cases of both influenza and COVID-19 and the “good vaccine” still needs two or three years

Academician Zhong Nanshan, a Chinese public health expert, said in a public speech that with the advent of winter and the outbreak of influenza, we will face patients with both influenza and COVID-19 in the future.

As for the vaccine that everyone is most concerned about, Zhong Nanshan said that currently some published experimental data are only one of the indicators, and factors such as production cost, transportation and preservation, and antibody maintenance time need to be considered. To find a “good vaccine” that can be used on a large scale, it currently takes at least two to three years.

Co-infection with COVID-19 and Flu


Multiple cases of co-infection with COVID-19 and Flu have been found

Zhong Nanshan mentioned in his speech that there have been 4 cases of both influenza A and COVID-19 in the feedback received so far. In fact, the co-infection of the COVID-19 flu has been reported as early as February this year.

In a study published on the preprinted paper platform medRxiv, Li Yan, director of the Laboratory of Wuhan University People’s Hospital, and others analyzed 8274 close contacts of COVID-19 from January 21, 2020 to February 9, 2020 , Found that 6 of the 316 patients were combined with other viral infections, including 3 cases of influenza A.

On May 14, Sun Tieying, a professor of the Department of Respiratory Medicine at Beijing Hospital and the director of the Department of Internal Medicine, mentioned that of the 50 severe cases of COVID-19 pneumonia admitted to Wuhan, 18 cases tested positive for influenza nucleic acid, and “there are many people who are co-infected by COVID-19 and influenza.”

Since then, Turkey, Iran, Japan, Bulgaria and other countries and regions have also reported co-infection cases of the COVID-19 combined with influenza.

A more detailed case comes from the China-Japan Friendship Hospital. A 69-year-old man with a history of living in Wuhan developed fever and dry cough on January 23. A nasopharyngeal swab showed positive for influenza A but negative for COVID-19. After being discharged from the hospital with oral oseltamivir, the patient developed persistent fever and worsening dyspnea on January 30, and returned to the hospital. The nasopharyngeal swab and sputum samples were all negative for COVID-19.

Subsequently, medical staff performed bronchoscopy on the case to obtain bronchoalveolar lavage fluid (BALF), and then performed metagenomic next-generation sequencing (mNGS) on BALF to determine the pathogen as COVID-19, and BALF RT-PCR Also tested positive for COVID-19. The patient was diagnosed with dual infection of COVID-19 and influenza A.

This case highlights two challenges in diagnosing COVID-19 under double infection.

On the one hand, the test that detects tCOVID-19 from upper respiratory tract samples may not be sensitive enough, and it also requires sputum samples and bronchoalveolar lavage fluid samples.

On the other hand, the differential diagnosis of COVID-19 and other respiratory diseases is very difficult, especially during the flu season. If a patient has a positive flu test but a false negative for the COVID-19, it is likely to cause misdiagnosis and missed diagnosis.

The incidence of influenza has decreased relative to previous years

In most parts of some countries, influenza, which is seasonal in winter and spring, can cause an average of 88,000 excess deaths from respiratory diseases each year, accounting for 8.2% of all deaths due to respiratory diseases. Especially for pregnant women, children, the elderly and patients with other chronic underlying diseases, the harm of influenza is more serious.

However, the relatively good news is that due to the almost complete overlap of the prevention and control measures of the COVID-19 and the flu, in the context of the COVID-19, the incidence of influenza in this autumn and winter may see a small drop.

The latest data from CDC shows that the COVID-19 prevention and control measures have shortened the 2019-2020 influenza season by 6 weeks compared with previous years. Since late January 2020, among the influenza-like cases received by sentinel hospitals across the country, the positive rate of influenza virus has dropped rapidly. Compared with the average level of previous years, the southern provinces have dropped by 63.9% and the northern provinces have dropped by 81.6%.

In addition to influenza viruses, other infectious diseases are also affected. From January to July this year, a total of 3744,135 cases of all 40 notifiable infectious diseases were reported, an average decrease of 25% over the same period in the past three years (2017-2019).

Despite this, the challenge of the dual pandemic of COVID-19 and flu still cannot be ignored

Similarly, respiratory symptoms are usually the main clinical manifestations, and the dual epidemic of influenza and COVID-19 has added a lot of difficulty to differential diagnosis.

Professor Ning Yi, executive dean of the Zhongguancun Meinian Institute of Public Health, pointed out that in this case, it is likely that “strikes and neglect coexist”, that is, attaches great importance to the COVID-19, but ignores the co-infection or dual epidemics. Threatened.

“For all patients with symptoms, we must first exclude COVID-19, which will put a certain differential diagnosis pressure on the medical system. On the other hand, because the symptoms are difficult to distinguish, individuals may have a fluke mentality about the disease, so there are also delays. The possibility of medical treatment and family transmission.”

Influenza vaccine production has increased, but supply still exceeds demand

Affected by the COVID-19 epidemic, this year’s flu vaccination has also undergone many changes.

In order to cooperate with the vaccination work, the first batch of influenza vaccines this year was issued one month earlier. According to, on July 14, the influenza vaccine produced by China Bio-Shanghai Institute of Biological Products obtained the first batch of domestic influenza vaccine biological products in 2020.

As of the end of August, a total of 10.54 million influenza vaccines had been issued, an increase of 52% year-on-year. Feng Luzhao, a professor at Peking Union Medical College, predicted that in 2020, the batch of influenza vaccines is expected to reach 50 million doses. However, Feng Luzhao also mentioned that 50 million dose batches can only cover 4% of China’s population.

In an interview with Caixin, some vaccine manufacturers stated that their current production capacity has increased by 30% to 40% year-on-year. If subsequent demand is large, the production time may be extended to November to December.

China’s latest “Influenza Vaccination Technical Guidelines (2020-2021)” recommends that recipients should be immunized before the end of October. However, due to the insufficient supply of vaccines, people who have not yet been vaccinated can obtain influenza vaccines through communities and hospitals throughout the epidemic season.