Ever since the report of AIDS-infected people in 1981, scientists have been searching for ways to control AIDS, firstly for a cure and secondly for prevention. There has been constant good news and bad news on both paths. On this side, it is said that there is an antiviral drug that can control the virus, and then it is announced that the virus has become resistant to the drug, and the effect of the drug developed is greatly reduced. On this side, it is said that there has been a breakthrough in the development of a vaccine, and then it is said that the test results are not good, and the vaccine development has failed. However, scientists did not give up because of the failure, and new antiviral drugs were constantly being developed, with better and better antiviral effects and lower and lower side effects.

It is well known that HIV belongs to the retrovirus, and the large mutation of HIV leads to the difficulty of vaccine development. Although the vaccine research has not been successful, researchers have gradually summed up their experience in the midst of repeated failures, and are on the way to the right path, and the protection effect of the vaccine developed is getting better and better.

Research on AIDS vaccines can be divided into four phases: the first phase is to study neutralizing antibodies for humoral immunity, in which recombinant soluble proteins are used to stimulate the body to produce neutralizing antibodies to eliminate HIV; the second phase is to study cellular immunity mediated by stimulation of CD8+ T-cells, in which viral vectors are used to activate the cellular pathway to kill and injure HIV specifically.... The third phase investigated the combination of humoral and cellular immunity, using "primary-boosted" combined immunity to inhibit viral replication and prevent HIV infection. Phase IV summarized the lessons learned from the first three phases, with vaccine design focusing more on antigenic modification and vector replication to induce stronger humoral and cellular immune responses.

AIDS vaccine development has been underway since 1987, and to date there are nearly 300 AIDS vaccine trials worldwide.including those that had entered phase III in 1998AIDSVAX developed by VaxGenvaccinations，However, in 2003, it was announced that the results of the trials had shown the vaccine to be ineffective. In the same year, an AIDS vaccine, RVl44, a collaboration between the U.S. military and the Thai government, entered clinical studies in Thailand.the only clinical trial to date with tens of thousands of participants.With 16,403 participants, the results of the 2009 trial showed thatThe last 51 of the 8197 vaccinated volunteers were infected with HIV, compared to 74 of the 8198 in the control group.The trial resulted in a vaccine protection rate of 31%, less than half, which is clearly not enough to meet the real needs, but still proves thatThe ability of the combination immunization strategy to reduce the risk of HIV infection in heterosexually susceptible individuals in the general population was an example of the "first alternative AIDS vaccine to successfully reduce the risk of HIV infection" and provided direction for subsequent vaccine research, which is now being continued by the RVl44 investigators. RV305 is also in the process of being developed.Phase II pilot study phase.

A vaccine trial conducted by Merck in 2004 even showed an increase in the rate of HIV infection in vaccinated individuals, and the trial was terminated in 2007.

End of 2013Researchers at Harvard Medical School and other institutions in the United States reported in the journal Cell that they have developed a "mosaic vaccine" utilizing the three major proteins of the AIDS virus, Env, Gag and Pol. The mosaic vaccine, also known as a "mosaic vaccine," is based on the analysis of a large number of viral gene sequences and the human immune response, and the use of artificially designed and optimized gene sequences to create a vaccine that induces a wider range of immune responses in the body, and covers all the common subtypes of the AIDS virus. After inoculating the rhesus monkeys with the vaccine, the researchers attacked them six times with the most pathogenic human-monkey chimeric immunodeficiency virus (SHIV), simulating a natural infection, to test the vaccine's effectiveness.At the end of the trial the researchers found that only three of the 12 vaccinated rhesus monkeys were healthy and unharmed after six consecutive attacks by the virus, although theAll 12 unvaccinated rhesus monkeys became infected after 3 attacks.However, calculations have shown that the "mosaic vaccine" protects rhesus monkeys by 87 to 90 percent.

In 2015, a phase I/II clinical trial of HVNTl00 was conducted in South Africa using a combination immunization strategy in 252 HIV-negative heterosexual subjects aged 18 to 40 years. Interim results showed that 80% of vaccinated individuals produced IgG responses against at least 1 of the 3 vaccine antigens.

The title mentions that this clinical trial by Johnson & Johnson is the 2013 Phase 1/2a clinical results of the Mosaic vaccine, and the Phase I clinical trial of the vaccine is focusing on observing the safety, and the target population should generally be healthy adults. The purpose of phase II trials is to observe or evaluate whether the vaccine can obtain the expected effect (usually referred to as immunogenicity) and general safety information in the target population. The purpose of phase III trials is to comprehensively evaluate the protective effect and safety of the vaccine, and this phase is the basis for obtaining registration approval. Phase IV clinical trial is a comprehensive evaluation of the safety and efficacy of the vaccine in the actual application population after the vaccine is registered and marketed.

　 The vaccine trial used a "primary-booster" strategy, in which subjects received a total of four vaccinations, the first two primary and the last two booster shots. Forty-eight weeks after the injections, the subjects had no side effects, and blood tests showed that all of them had developed antibodies against HIV. In an assessment of the actual protection of the subjects, the risk of HIV infection was reduced by 94%, which was similar to, or even better than, the results of animal testing.

However, because the number of subjects in the clinical trial is relatively small, only the next phase III trial can truly verify the effectiveness of the vaccine, after all, there have been precedents of ever entering phase III and failing. Only if Phase III is successful will the vaccine have a real chance of being marketed. Until then, we still have to rely on existing strategies such as early detection of infected people, treatment of infected people, and cleanliness to control AIDS.

Even if the vaccine were available, how many people would be willing to be vaccinated against AIDS?

This is another sensation created by the Chinese network for the sake of clicks, and this news from Johnson & Johnson only has a bigger echo in the Chinese network.

I was once involved in the development of the HIV vaccine, and the AIDS vaccine, from its inception to the present day, is still in the position of having a long way to go. Hope is not lacking, but no substantial breakthrough can be seen yet.

100% antibody production and 100% protection rate are not the same concept, indicating that it is possible for this vaccine to induce antibodies in all the vaccinated people, which is the basic requirement for the HIV vaccine. If it can only stimulate antibodies in 70% or 80% of the vaccinated people, then it is not as effective as the existing preventive measures, because the vaccination will give people an impression that they do not need to take extra precautions, and previous clinical trials of HIV vaccines have shown that the vaccination group has a higher rate of HIV infection than the control group because the vaccinated people think that they are invulnerable to the vaccine, and they do not take precautions during sex, and those experimental vaccines do not work satisfactorily. The vaccine in those trials did not work well, but instead facilitated the spread of HIV.

If antibodies are produced, it depends on whether they can prevent HIV infection. In many cases, antibodies are present but do not prevent infection, and such immunization is not specific immunity. Whether this vaccine can prevent infection is still unclear, and will depend on the results of the next few phases of clinical trials.

The report says, "In addition to producing antibodies against HIV in 100% of the subjects, it also reduced the risk of infection from a single exposure to the AIDS virus (HIV) by 94%, and 66% were still protected from HIV infection after six exposures." I don't know if it was inadvertent or intentional, but the first statement about antibody production was a human test result from an early clinical trial, and the second paragraph about the 94% and 66% figures says that it was a previous result in monkeys, and that no similar validated human trials have been done, and again, you can't go on the attack with HIV because it's unethical. One can only track these vaccinated people who are in a high prevalence area, over time, and see what their infection rate is, and compare it to a control group.

The monkey test was done with monkey HIV, which is not the same as human HIV.

The originator of this story would be excusable if it was a matter of foreign language proficiency, but if it was intentional, it's a rumor.

Taking a step back, even if the results of "94% reduction in the risk of infection from a single exposure to HIV and 66% protection from six exposures" were obtained in a population, this is not ideal for an HIV vaccine, i.e., with only 66% protection, it is unlikely that it would be approved. likely to be approved.

Hopefully, this vaccine will get even better results in later clinical trials, but for now, there's nothing to cheer about.

Is there a vaccine for AIDS?

There is currently no approved AIDS vaccine on the market worldwide. Although there is a vaccine in development, it is not yet known whether it will ultimately be effective in preventing AIDS.

AIDS does not yet have a vaccine for the following reasons: ① AIDS pathogen for the human immunodeficiency virus (HIV), this virus has a strong replication capacity, rapid mutation, the body's immune system is difficult to cope with; ② HIV's immune protection mechanism is not completely clear, people infected with viruses such as hepatitis A virus, hepatitis B virus and other viruses can stimulate the body's immune system to produce antibodies to clear the virus, or can be effectively controlled, so that the person becomes a healthy carriers, but it is difficult to induce the host to produce protective immunity after natural HIV infection, which also brings difficulties for vaccine development; ③ There is no suitable animal model.

AIDS is mainly contracted through sexual transmission, blood transmission and mother-to-child transmission. Although there is no vaccine, measures can be taken to effectively prevent it.

Preventive measures include: ① use condoms, avoid high-risk sexual behavior; ② do not transfuse blood or use blood products without authorization, should be used under the guidance of a professional doctor; ③ do not share syringes with others, drug use is strictly prohibited; ④ AIDS pregnant women to do a good job of mother-to-child interruption during delivery, to prevent vertical transmission; ⑤ to avoid direct contact with the blood of patients with HIV, feces, secretions, cut off the transmission pathway.

This content was reviewed by Dr. Li Dongzeng, Deputy Chief Physician, Department of Infection, Beijing You'an Hospital, Capital Medical University.

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