Coronavirus vaccines: Your questions answered – CNN

Vaccinations could begin in the United States in the second half of December, starting with high-risk groups and becoming available for the rest of the population in spring, according to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

Here are some answers to common questions about the coronavirus vaccines being developed to prevent Covid-19.

Don't vaccines take years to develop safely? How have these two been developed in just 10 months?

The pandemic has galvanized the scientific community all around the world, with groups of researchers in dozens of countries on a fast-paced hunt to understand how the virus works.

Operation Warp Speed has also drawn up protocols to allow trials to proceed more quickly, and industrial-scale manufacturing of the vaccines has taken place before we knew whether they would be effective. This means we have millions of doses ready to be used.

How effective is this vaccine?

In Moderna's trial, 15,000 study participants were given a placebo, which is a shot of saline that has no effect. Over several months, 90 of those people developed Covid-19. Another 15,000 participants were given the vaccine, and five of them developed Covid-19.

Among those receiving a placebo, 11 became severely ill, but none of the participants who received the vaccine became severely ill.

The head of the International Vaccine Institute has hailed biotech company Moderna's early data on its Covid-19 vaccine candidate, saying it is "proof of concept," but cautioned that it's still early days in terms of follow-up efficacy.

"I think it's really great news and in a way confirmation that the RNA vaccines are able to protect against infectious disease and it is also a good example again that Covid vaccines are a possibility," Dr. Jerome Kim, the institute's director general, told CNN on Monday.

"It will be really important to know what efficacy is - not at two months, but at six and twelve," Kim said.

There are still lots of unknowns about how the new coronavirus vaccines would work in practice. It's not clear whether they would prevent infection altogether or make severe illness less likely. Doctors also do not know how long their protection will last.

Vaccines have various efficacy rates. According to the US Centers for Disease Control and Prevention, a full round of polio vaccines is 99% to 100% effective; full vaccination against diphtheria, tetanus and pertussis is 80% to 90% effective, while the efficacy of flu vaccine varies from year to year.

How safe are the vaccines, and are there any side effects?

Moderna said its vaccine did not have any significant side effects. A small percentage of those who received it experienced symptoms such as body aches and headaches. It's similar to what people might experience after a flu shot and is a sign the vaccine is working to create an immune defense.

"They report no safety concerns - the main side effects are injection site pain, fatigue, muscle or joint aches and pains and headache which seemed to occur more frequently after the second injection," Dr. Penny Ward, a visiting professor in pharmaceutical medicine at King's College London, told the SMC.

"Clearly we still need to see the complete scientific details in a publication to be able to judge the outcomes independently."

How do these vaccines work? I'm worried they sound experimental.

Vaccines typically mimic part of the virus they protect against, prompting a response from your immune system.

The vaccines from Moderna and Pfizer both use a new approach that hasn't resulted in an approved vaccine before -- although they have been studied in clinical trials for other viruses.

The two vaccines use genetic code rather than any part of the virus itself, with a technique called messenger RNA, or mRNA. The vaccines deliver mRNA, which is a genetic recipe. In this case, the genetic recipe directs cells to make pieces of the spikes that sit atop the coronavirus. Once it's injected, the body's immune system makes antibodies that recognize these spikes. If a vaccinated person is later exposed to the coronavirus, those antibodies should stand at the ready to attack the virus.

The fact that Moderna and Pfizer have independently produced very similar results using the same technique is a vote of confidence in the genetic technology, experts said, and their results could make it much easier and quicker to produce other vaccines.

"Using this technology, vaccine candidates can be produced substantially faster in the future to combat virtually any infectious disease, by producing vaccines against both existing pathogens and future, currently unknown pathogens," Zoltn Kis, research associate at the Future Vaccine Manufacturing Hub, Imperial College London, told the SMC.

Other companies are developing vaccines using other techniques -- the Oxford/AstraZeneca vaccine is made from a harmless modified chimpanzee virus, while the traditional route is to use the inactivated virus.

Sign me up! When can I get it?

While Fauci said he expects the first Covid-19 vaccinations to begin toward the latter part of December, initially there won't be enough vaccine for everyone. The highest-priority groups, which include health care workers, the elderly and people with underlying medical conditions, will get the vaccine first.

"I think that everybody else will start to get vaccinated towards the end of April," Fauci said. "And that will go into May, June, July. It will take a couple of months to do."

The British government has asked the National Health Service, known as NHS, to be ready to deploy a vaccine from the beginning of December.

What if I'm old, pregnant or clinically vulnerable?

The study also includes more than 11,000 participants from communities of color, representing 37% of the study population, which Moderna said was similar to the diversity of the US population. This includes more than 6,000 participants who identify as Hispanic or Latinx, and more than 3,000 participants who identify as Black or African American.

Noubar Afeyan, the co-founder and chairman of Moderna, said the company doesn't see "any difference in the results," among the subgroups in its Covid-19 vaccine trials.

"Moderna actually slightly slowed down the trial recruitment to ensure that we had a substantial representation, and it turns out, 37% of our trials were people, were subjects, that are considered of color," Afeyan said on CNN International Monday.

"Generally, it looks like the vaccine performs broadly across all the population groups," Afeyan said.

However, we don't know anything about groups not involved in the trial such as children or pregnant women.

"Urgent questions remain to be answered, including how long these vaccines will be effective for and whether these vaccines work across different populations, in all age groups, ethnicities, and those with prior health conditions," said Charlie Weller, head of vaccines at medical research charity Wellcome.

"Only upon trial completion will we be able to assess the full efficacy and safety of any vaccine candidate."

Will the vaccines be compulsory? What happens if I decide not to get vaccinated?

If you decide against getting a vaccination, it does have wider implications. Not only will you not have protection against Covid-19, but it could potentially make it harder to achieve community, or herd, immunity. This protects high-risk groups that might not be able to get the vaccination.

It is estimated that a Covid-19 vaccine will need to be accepted by at least 55% of the population to provide community immunity, according to the London School of Hygiene & Tropical Medicine, and some scientists anticipate even higher numbers will be needed.

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Coronavirus vaccines: Your questions answered - CNN