Im certainly concerned with the trajectory, Dr. Scott Roberts, associate medical director of infection prevention at Yale New Haven Hospital, tells Fortune. Its almost an exponential rise right now.

With the surge in RSV cases and continued COVID outbreaks, in what many experts flag as a tripledemic, this holiday season may prove difficult. Experts recommend those six months and older get the flu vaccine, which targets four different strains of the flu, similar to how COVID vaccines have shifted to combat the different variants, Roberts says. 

How effective is the flu shot this year?

The U.S. follows how the flu manifests in the southern hemisphere during their winter flu season to cast predictions on what will happen during our prime season, and therefore, some years the flu vaccine is more effective than other years depending on the strain. It tends to be a good season if the vaccine is 40% to 60% effective, Roberts says. 

This years flu shot has a nearly 50% efficacy against hospitalization from the major strain of the flu, according to the CDC.

The flu vaccine works to reduce the spread of influenza, along with the number of hospitalizations and deathsit works to help prevent a bad outcome in those who get sick Roberts says. It can also reduce the risk of getting diagnosed with the flu, while not full proof. 

The primary goal of it is actually to reduce the severity of disease, not necessarily to fully prevent any infection from occurring. Thats quite difficult to do with flu because it mutates so rapidly, Roberts says. The vaccines do what theyre designed to do, which is to prevent people from dying and going to the hospital. Even if you get the flu, the chances of hospitalization and death are much lower than having not gotten the vaccine. The efficacy depends on how well the vaccine matches the strain of the virus each year. 

When is the flu shot most protective? 

People are most protected from the flu two weeks post vaccine when the body has enough time to generate antibodies needed to fight the virus. 

Depending on how the flu mutates that season, people may be more susceptible to getting the flu, Roberts explains; people may respond to the vaccine differently depending on when they get it in the season. 

As the virus mutates further, the risks of my antibody not responding to it or not being able to effectively kill it go down over time, he says, and that someone who got the flu vaccine in September may be more prone to getting sick when infected in December than someone who had gotten the vaccine in November if the virus mutates, for example. 

Generally, because flu cases start to rise in early November, Roberts recommends getting vaccinated in October, but its not too late to get vaccinated now. While the level of protection someone will receive is patient dependent, Roberts says getting the flu shot will boost your chances of not getting severely sick.

In the 2019-2020 flu season, the CDC estimates that the vaccine prevented 7.5 million flu cases, over 100,000 hospitalizations and over 6,000 deaths. 

Who responds well to the flu shot? 

Age and health also factor into the efficacy of the flu shot, the CDC says. People younger than 65 tend to have more protection against the flu after getting the shot. The CDC recommends three specific flu vaccines for those 65 and older: Fluzone High-DoseQuadrivalent vaccine, Flublok Quadrivalent recombinantflu vaccine and Fluad Quadrivalent adjuvanted flu vaccine.

For someone going through chemotherapy or with a suppressed immune system, their body might not be able to generate the antibodies needed to fight off a virus, Roberts says. Its important for people in those categories to speak to their doctor about additional ways to stay protected.

If the specific vaccine youre looking for isnt being offered, experts say getting vaccinated with the one available is still the best call.

Is the flu shot still worth it? 

Experts say absolutely. While vaccines dont 100% protect people from infection, they collectively help reduce the risk of severe illness and hospital overwhelm. 

Its a no brainer to get it now, Roberts says, especially as people gather together with loved ones and those who may be immunocompromised or at higher risk for getting severely sick.

Sign up for the Fortune Features email list so you dont miss our biggest features, exclusive interviews, and investigations.

China has taken one of the worlds strictest approaches to handling the coronavirus, and unlike most countries, it is continuing to pursue the elimination of COVID-19 from its population.

Earlier this year, Shanghai was forced into a lockdown that lasted two months, with the city reopening in June before reinforcing strict measures in some of the citys districts in October.

But Chinese citizens are taking an unusually vocal stand against officials as the pandemic has trudged on and residents freedom has remained at the mercy of the virus.

As Chinas draconian measures have ebbed and flowed, residents have been seen protesting, attacking health officials enforcing the shutdowns and screaming from the windows of the apartments in which theyve been trapped.

While some evidence of the pushback has been shared on Chinese social media platforms, the governments censors have worked to quickly eradicate criticisms of its controversial zero-COVID strategy from circulation.

However, residents of Guangzhoua manufacturing city close to Hong Kong with a population of more than 10 millionhave found that using their regional dialect on Weibo, Chinas answer to Twitter, has helped them vent their frustrations.

Guangzhou has seen restrictions tightened in recent days as cases of COVID have ticked upward, prompting concerns and complaints from the citys inhabitants.

Locals speak Cantonese, which is distinctly different from Mandarin, Chinas official language. Mandarin speakersand censorsmay have some trouble understanding Cantonese slang, obscenities and wordplay, and it appears the differences have helped some complaints about COVID restrictions evade Chinese content controls.

We had to lock down in April, and then again in November, one Weibo user from the city said in a post on the platform on Monday. The government hasnt provided subsidies do you think my rent doesnt cost money?

The individual went on to use slurs and insult officials.

Watching Cantonese people scolding [government] on Weibo without getting caught, another reportedly wrote, alongside characters that symbolize laughing. Learn Cantonese well, and go across Weibo without fear.

Media monitoring organization China Digital Times, which is associated with the University of California, Berkeley, said in September that because Weibos censorship system might have difficulty recognizing Cantonese spellings, many posts that feature spicy, bold and straightforward language were able to survive.

But if the same content is written in Mandarin, it is likely to be blocked or deleted, the organization said. In this regard, some netizens commented that Cantonese text is contemporary encrypted text.

Every place must protect its own language, so that it will not be deleted when it wants to speak out, one Weibo user said in a post highlighted by China Digital Times.

As well as sparking frustration and fear among its population, Chinas approach to COVID-19 has sparked widespread concerns about the global economy and a rare criticism of the Chinese government from the WHO itself.

When we talk about the zero-COVID strategy, we dont think its sustainable considering the behavior of the virus now and what we anticipate in the future, WHO Director-General Tedros Adhanom Ghebreyesus said in May. His comments were reportedly censored on Chinese internet platforms.

Last week, China reiterated its commitment to the zero-COVID policy, with its top leadership body calling for unwavering support of the strategy.

Sign up for the Fortune Features email list so you dont miss our biggest features, exclusive interviews, and investigations.