如何看待美国内华达州发现的世界首例导致严重症状的新冠二次感染病例？

Nevada's First Severe COVID19 Reinfection Case: A Detailed Look

The emergence of the first documented case of severe COVID19 reinfection in Nevada is a significant development that warrants a thorough examination. It's crucial to understand what this case signifies, its implications for public health, and the broader context of viral evolution and immunity.

What is COVID19 Reinfection?

Before delving into the specifics of the Nevada case, it's important to clarify what reinfection means in the context of COVID19. Generally, reinfection refers to a person contracting the SARSCoV2 virus a second time after having recovered from a previous infection. This can occur due to several factors:

Waning Immunity: The immunity acquired from a previous infection, whether natural or vaccineinduced, can decrease over time.
Viral Evolution (New Variants): The virus itself can mutate and evolve, leading to new variants that may partially evade the immune response developed against earlier strains. This means that even if immunity is present, it might not be as effective against a newer, different variant.
Incomplete Immune Response: In some individuals, the initial infection might not have generated a sufficiently robust or longlasting immune response.

The Nevada Case: A Closer Examination

While specific details of individual patient cases are often kept private due to HIPAA (Health Insurance Portability and Accountability Act) regulations in the US, public health agencies like the Nevada Department of Health and Human Services (NDHHS) and the Centers for Disease Control and Prevention (CDC) are responsible for tracking and reporting such significant findings.

Let's break down what such a case likely entails and how it would be identified and reported:

1. Initial Infection: The individual would have previously tested positive for SARSCoV2. This could have been symptomatic or asymptomatic. They would have recovered from this initial infection. During this period, their immune system would have mounted a response, producing antibodies and Tcells.

2. Interval Between Infections: A crucial aspect of reinfection is the time elapsed between the first and second infection. Public health definitions often require a minimum period (e.g., 90 days) to distinguish reinfection from a prolonged or relapsing initial infection.

3. Second Positive Test: The individual would subsequently test positive for SARSCoV2 again, after having recovered from the first infection. This second positive test would typically be with a different viral specimen than the first.

4. Identification of Different Viral Strains (Often): To definitively confirm reinfection, especially with a distinct clinical presentation, genomic sequencing is often employed. This process analyzes the genetic material of the virus from both infection episodes. If the genetic sequences of the virus from the first and second infections show significant differences, it strongly suggests infection with different strains or variants of SARSCoV2. This is a key indicator, particularly if the second infection is due to a variant that has emerged since the first infection.

5. Severe Symptoms in the Second Infection: The "severe symptoms" aspect is what makes this case particularly noteworthy. It implies that the second infection resulted in more serious outcomes compared to the first, or perhaps the first infection was mild or asymptomatic, and the second was severe. Severe symptoms could include:
Hospitalization
Requiring intensive care unit (ICU) admission
Needing mechanical ventilation
Developing pneumonia, acute respiratory distress syndrome (ARDS), or other significant organ damage
Death

6. Public Health Investigation and Reporting: When such a case is identified, public health authorities would likely conduct a thorough investigation. This would involve:
Contact Tracing: To understand the source of both infections and identify potential contacts who may also be infected.
Case Definition Review: Ensuring the case meets the criteria for reinfection as defined by public health bodies.
Genomic Sequencing: As mentioned earlier, this is crucial for confirming that the second infection is indeed with a different strain, especially if a new variant of concern is circulating.
Data Collection: Gathering information about the patient's age, underlying health conditions (comorbidities), vaccination status (if applicable), the severity of symptoms in both infections, and treatment received.
Public Notification: Informing the public about the findings to raise awareness and guide public health strategies.

Implications of the Nevada Case and COVID19 Reinfection in General:

Waning Immunity is Real: This case reinforces the understanding that immunity, whether from infection or vaccination, is not necessarily permanent. The duration and strength of immunity can vary among individuals and may also be influenced by the specific variant encountered.
The Role of Variants: The emergence of new variants is a significant driver of reinfections. Variants like Delta and Omicron, with their increased transmissibility and potential to partially evade immune responses, have been linked to higher rates of reinfection. If the Nevada case involved a new variant, it would highlight the ongoing challenge of adapting public health measures to viral evolution.
Vaccination Remains Crucial: While reinfection is possible, vaccines are still considered highly effective in preventing severe illness, hospitalization, and death, even against new variants. Understanding the vaccination status of the individual in the Nevada case would be critical. If they were unvaccinated, it underscores the importance of vaccination. If they were vaccinated, it might suggest that vaccines, while highly protective, don't offer absolute protection against all forms of infection, but they likely still significantly reduced the risk of severe outcomes.
Public Health Strategies Need to Adapt: The possibility of reinfection means that public health strategies must remain dynamic. This includes:
Ongoing Surveillance: Monitoring for new variants and tracking reinfection rates.
Booster Doses: Recommending booster shots to bolster immunity as it wanes or becomes less effective against new variants.
Continued Public Health Messaging: Educating the public about the ongoing risk of infection and the importance of preventive measures like masking (especially in hightransmission settings), vaccination, and good hygiene.
Research into LongTerm Immunity: Continued research is needed to understand the factors that contribute to lasting immunity and to develop vaccines that offer broader and more durable protection.

What is NOT necessarily implied by this single case:

It's important to avoid overstating the implications of a single case. While significant, one documented instance doesn't automatically mean that reinfections are becoming widespread or that current vaccines are ineffective. Public health officials will be looking for patterns and trends across multiple cases.

In summary, the discovery of the first severe COVID19 reinfection case in Nevada is a concerning yet informative event. It serves as a stark reminder that the pandemic is still evolving, and the virus continues to present challenges. This case underscores the importance of continued vigilance, adherence to public health guidance, ongoing research into viral evolution and immunity, and the critical role of vaccination and booster doses in protecting individuals and communities from severe outcomes.

1、这个病毒着实顽固。基本可以宣告押宝“群体免疫”赌国运要输光底裤了。

2、拥有地球最先进的生物科技的美国，押宝疫苗，看来也是一场国运豪赌了。病毒变来变去，疫苗能不能赶上病毒变化是个问题。即使不断更新疫苗，几亿人隔三差五去打疫苗也是不现实的事情。

3、指望病毒的变异向着和人类共存的方向，于是传染性变强、致病致死性变弱，看来也不一定成立。

4、天花和人类共存了500-600年，最终被疫苗终结。人类想要进化出适应病毒的体质，最少也要500-600年吧。

5、如果疫情几年都不消退，人类世界可能会演化出新的生活方式。可能更倚重网络生活、信息社会，人际接触减少，出行频率降低，以免反复感染，造成生命危险。

就2020年的时局而言，大政府好过小政府，小政府好过无政府，这句话已经可以基本认定为无例外的真理了。

有的朋友可能要问了，不对呀，不是说大政府有大政府的好，小政府有小政府的好吗？是的，这话本来是没错的，但那是在2019年。就2020年的时局来看，我暂时还没发现有哪一家是政府过大、组织力过强了，各国只有“集权程度稍差”，“集权程度很差”，“集权程度极差”之分。大家都是饿到不同程度的非洲饥民，有鸡腿就一定要无脑吃，均不存在胆固醇过高的问题。

面对病毒，“利维坦”毫无疑问是个褒义词，当然我到现在还没见到哪一家配称自己是利维坦的。当今时局，我只见过“实质联邦”，“实质邦联”，“名义邦联”和“索马里试验田”四种模式。大家对号入座吧，总之。