Will the COVID vaccine make me test positive for the coronavirus? 5 questions about vaccines and COVID testing answered

COVID-19 vaccination is rolling out across Australia. So health authorities are keen to dispel myths about the vaccines, including any impact on COVID testing.

Do the vaccines give you COVID, or make you test positive for COVID? Does the vaccine affect other tests? Do we still need to get COVID tested if we have symptoms, even after getting the shot? And will we still need COVID testing once more of the population gets vaccinated?

We look at the evidence to answer five common questions about the impact of COVID vaccines on testing.

Read more: Do I need to register for a COVID vaccine? How will I know when it's my turn? Vaccine rollout questions answered

1. Will the vaccine give me COVID?

The short answer is “no”. That’s because the vaccines approved for use so far in Australia and elsewhere don’t contain live COVID virus.

The Pfizer/BioNTech vaccine contains an artificially generated portion of viral mRNA (messenger ribonucleic acid). This carries the specific genetic instructions for your body to make the coronavirus’s “spike protein”, against which your body mounts a protective immune response.

The AstraZeneca vaccine uses a different technology. It packages viral DNA into a viral vector “carrier” based on a chimpanzee adenovirus. When this is delivered into your arm, the DNA prompts your body to produce the spike protein, again stimulating an immune response.

Any vaccine side-effects, such as fever or feeling fatigued, are usually mild and temporary. These are signs the vaccines are working to boost your immune system, rather than signs of COVID itself. These symptoms are also common after routine vaccines.

2. Will the COVID vaccine make me test positive?

No, a COVID vaccine will not affect the results of a diagnostic COVID test.

The current gold-standard diagnostic test is known as nucleic acid PCR testing. This looks for the mRNA (genetic material) of SARS-CoV-2, the virus that causes COVID-19. This is a marker of current infection.

This is the test the vast majority of people have when they line up at a drive-through testing clinic, or attend a COVID clinic at their local hospital.

Yes, the Pfizer vaccine contains mRNA. But the mRNA it uses is only a small part of the entire viral RNA. It also cannot make copies of itself, which would be needed for it to be in sufficient quantity to be detected. So it cannot be detected by a PCR test.

The AstraZeneca vaccine also only contains part of the DNA but is inserted in an adenovirus carrier that cannot replicate so cannot give you infection or a positive PCR test.

Read more: How mRNA vaccines from Pfizer and Moderna work, why they're a breakthrough and why they need to be kept so cold

3. How about antibody testing?

While PCR testing is used to look for current infection, antibody testing — also known as serology testing — picks up past infections.

Laboratories look to see if your immune system has raised antibodies against the coronavirus, a sign your body has been exposed to it. As it takes time for antibodies to develop, testing positive with an antibody test may indicate you were infected weeks or months ago.

But your body also produces antibodies as a response to vaccination. That’s the way it can recognise SARS-CoV-2, the next time it meets it, to protect you from severe COVID.

So as COVID vaccines are rolled out, and people develop a vaccine-induced antibody response, it may become difficult to differentiate between someone who has had COVID in the past and someone who was vaccinated a month ago. But this will depend on the serology test used.

Read more: Antibody tests: to get a grip on coronavirus, we need to know who's already had it

The good news is that antibody testing is not nearly as common as PCR testing. And it’s only ordered under limited and rare circumstances.

For instance, when someone tests positive with PCR, but they are a false positive due to the characteristics of the test, or have fragments of virus lingering in the respiratory tract from an old infection, public health experts might request an antibody test to see whether that person was infected in the past. They might also order an antibody test during contact tracing of cases with an unknown source of infection.

Read more: Why can't we use antibody tests for diagnosing COVID-19 yet?

4. If I get vaccinated, do I still need a COVID test if I have symptoms?

Yes, we will continue to test for COVID as long as the virus is circulating anywhere in the world.

Even though the COVID vaccines are looking promising in preventing people from getting seriously sick or dying, they won’t provide 100% protection.

Real-world data suggests some vaccinated people can still catch the virus, but they usually only get mild disease. We are unsure whether vaccinated people will be able to potentially pass it to others, even if they don’t have any symptoms. So it’s important people continue to get tested.

Furthermore, not everyone will be eligible to receive a COVID-19 vaccine. For instance, in Australia, current guidelines exclude people under 16 years of age, and those who are allergic to ingredients in the vaccine. And although pregnant women are not ruled out from receiving the vaccine, it is not routinely recommended. This means a proportion of the population will remain susceptible to catching the virus.

We also are unsure about how effective vaccines will be against emerging SARS-CoV-2 variants. So we will continue to test to ensure people are not infected with these strains.

Read more: UK, South African, Brazilian: a virologist explains each COVID variant and what they mean for the pandemic

We know testing, detecting new cases early and contact tracing are the core components of the public health response to COVID, and will continue to be a priority from a public health perspective.

Minimum numbers of daily COVID tests are also needed so we can be confident the virus is not circulating in the community. As an example, New South Wales aims for 8,000 or more tests a day to maintain this peace of mind.

Continued vigilance and high rates of testing for COVID will also be important as we enter the flu season. That’s because the only way to differentiate between COVID and influenza (or any other respiratory infection) is via testing.

5. Will testing for COVID stop as time goes on?

It is unlikely our approach to COVID testing will change in the immediate future. However, as COVID vaccines are rolled out and since COVID is likely to become endemic and stay with us for a long time, the acute response phase to the pandemic will end.

So COVID testing may become part of managing other infectious diseases and part of how we respond to other ongoing health priorities.

Read more: Coronavirus might become endemic – here's how

Meru Sheel, Epidemiologist | Senior Research Fellow, Australian National University; Charlee J Law, Epidemiologist | Research Associate, Australian National University, and Cyra Patel, PhD candidate, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fine particle air pollution is a public health emergency hiding in plain sight

Ambient air pollution is the largest environmental health problem in the United States and in the world more generally. Fine particulate matter smaller than 2.5 millionths of a meter, known as PM2.5, was the fifth-leading cause of death in the world in 2015, factoring in approximately 4.1 million global deaths annually. In the United States, PM2.5 contributed to about 88,000 deaths in 2015 – more than diabetes, influenza, kidney disease or suicide.

Current evidence suggests that PM2.5 alone causes more deaths and illnesses than all other environmental exposures combined. For that reason, one of us (Douglas Brugge) recently wrote a book to try to spread the word to the broader public.

Developed countries have made progress in reducing particulate air pollution in recent decades, but much remains to be done to further reduce this hazard. And the situation has gotten dramatically worse in many developing countries – most notably, China and India, which have industrialized faster and on vaster scales than ever seen before. According to the World Health Organization, more than 90 percent of the world’s children breathe air so polluted it threatens their health and development.

As environmental health specialists, we believe the problem of fine particulate air pollution deserves much more attention, including in the United States. New research is connecting PM2.5 exposure to an alarming array of health effects. At the same time, the Trump administration’s efforts to support the fossil fuel industry could increase these emissions when the goal should be further reducing them.

Where there’s smoke …

Particulate matter is produced mainly by burning things. In the United States, the majority of PM2.5 emissions come from industrial activities, motor vehicles, cooking and fuel combustion, often including wood. There is a similar suite of sources in developing countries, but often with more industrial production and more burning of solid fuels in homes.

Wildfires are also an important and growing source, and winds can transport wildfire emissions hundreds of miles from fire regions. In August 2018, environmental regulators in Michigan reported that fine particles from wildfires burning in California were impacting their state’s air quality.

Most deaths and many illnesses caused by particulate air pollution are cardiovascular – mainly heart attacks and strokes. Obviously, air pollution affects the lungs because it enters them as we breathe. But once PM enters the lungs, it causes an inflammatory response that sends signals throughout the body, much as a bacterial infection would. Additionally, the smallest particles and fragments of larger particles can leave the lungs and travel through the blood.

Emerging research continues to expand the boundaries of health impacts from PM2.5 exposure. To us, the most notable new concern is that it appears to affect brain development and has adverse cognitive impacts. The smallest particles can even travel directly from the nose into the brain via the olfactory nerve.

There is growing evidence that PM2.5, as well as even smaller particles called ultrafine particles, affect children’s central nervous systems. They also can accelerate the pace of cognitive decline in adults and increase the risk in susceptible adults of developing Alzheimer’s disease.

PM2.5 has received much of the research and policy attention in recent years, but other types of particles also raise concerns. Ultrafines are less studied than PM2.5 and are not yet considered in risk estimates or air pollution regulations. Coarse PM, which is larger and typically comes from physical processes like tire and brake wear, may also pose health risks.

Regulatory push and pull

The progress that developed countries have made in addressing air pollution, especially PM, demonstrates that regulation works. Before the U.S. Environmental Protection Agency was established in 1970, air quality in Los Angeles, New York and other major U.S. cities bore a striking resemblance to Beijing and Delhi today. Increasingly stringent air pollution regulations enacted since then have protected public health and undoubtedly saved millions of lives.

But it wasn’t easy. The first regulatory limits on PM2.5 were proposed in the 1990s, after two important studies showed that it had major health impacts. But industry pushback was fierce, and included accusations that the science behind the studies was flawed or even fraudulent. Ultimately federal regulations were enacted, and follow-up studies and reanalysis confirmed the original findings.

Now the Trump administration is working to reduce the role of science in shaping air pollution policy and reverse regulatory decisions by the Obama administration. One new appointee to the EPA’s Science Advisory Board, Robert Phalen, a professor of medicine at the University of California, Irvine, is known for asserting that modern air is actually too clean for optimal health, even though the empirical evidence does not support this argument.

On Oct. 11, 2018, EPA Administrator Andrew Wheeler disbanded a critical air pollution science advisory group that dealt specifically with PM regulation. Critics called this an effort to limit the role that current scientific evidence plays in establishing national air quality standards that will protect public health with an adequate margin of safety, as required under the Clean Air Act.

Opponents of regulating PM2.5 in the 1990s at least acknowledged that science had a role to play, although they tried to discredit studies that supported the case for regulation. The new approach seems to be to try to cut scientific evidence out of the process entirely.

No time for complacency

In late October 2018, the World Health Organization convened a special conference on global air pollution and health. The agency’s heightened interest appears to be motivated by risk estimates that show air pollution to be a concern of similar magnitude to more traditional public health targets, such as diet and physical activity.

Conferees endorsed a goal of reducing global deaths from air pollution by two-thirds by 2030. This is a highly aspirational target, but it may focus renewed attention on strategies such as reducing economic barriers that make it hard to deploy pollution control technologies in developing countries.

In any case, past and current research clearly show that now is not the time to move away from regulating air pollution that arises largely from burning fossil fuels, in the United States or abroad.

Doug Brugge, Professor of Public Health and Community Medicine, Tufts University and Kevin James Lane, Assistant Professor of Environmental Health, Boston University

This article is republished from The Conversation under a Creative Commons license. Read the original article.